WO2014069015A1 - Master cylinder - Google Patents

Master cylinder Download PDF

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Publication number
WO2014069015A1
WO2014069015A1 PCT/JP2013/058948 JP2013058948W WO2014069015A1 WO 2014069015 A1 WO2014069015 A1 WO 2014069015A1 JP 2013058948 W JP2013058948 W JP 2013058948W WO 2014069015 A1 WO2014069015 A1 WO 2014069015A1
Authority
WO
WIPO (PCT)
Prior art keywords
piston
inner peripheral
peripheral lip
cylinder
surface portion
Prior art date
Application number
PCT/JP2013/058948
Other languages
French (fr)
Japanese (ja)
Inventor
聖子 田邊
伸哉 河西
Original Assignee
日立オートモティブシステムズ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日立オートモティブシステムズ株式会社 filed Critical 日立オートモティブシステムズ株式会社
Priority to US14/430,317 priority Critical patent/US10053076B2/en
Priority to IN2357DEN2015 priority patent/IN2015DN02357A/en
Priority to JP2014544334A priority patent/JP5903496B2/en
Priority to CN201380048515.2A priority patent/CN104661885B/en
Priority to DE112013005217.2T priority patent/DE112013005217T5/en
Priority to RU2015110698/11A priority patent/RU2595334C1/en
Priority to KR1020157007927A priority patent/KR102089119B1/en
Publication of WO2014069015A1 publication Critical patent/WO2014069015A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
    • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
    • B60T11/16—Master control, e.g. master cylinders
    • B60T11/236—Piston sealing arrangements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T11/00—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant
    • B60T11/10—Transmitting braking action from initiating means to ultimate brake actuator without power assistance or drive or where such assistance or drive is irrelevant transmitting by fluid means, e.g. hydraulic
    • B60T11/16—Master control, e.g. master cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/18—Sealings between relatively-moving surfaces with stuffing-boxes for elastic or plastic packings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
    • F16J15/3204—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip
    • F16J15/3232—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip having two or more lips
    • F16J15/3236—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip having two or more lips with at least one lip for each surface, e.g. U-cup packings

Definitions

  • the present invention relates to a master cylinder that supplies hydraulic pressure to a brake cylinder of a vehicle.
  • Some master cylinders are provided with a piston seal having an inner peripheral lip portion in a circumferential groove of a cylinder body, and the inner peripheral lip portion of the piston seal is in sliding contact with the piston (see, for example, Patent Document 1).
  • master cylinders are provided with a cup-shaped seal and a sliding ring that is in sliding contact with the cylinder body in an annular groove of a piston (see, for example, Patent Document 2).
  • the present invention provides a master cylinder capable of suppressing the inner peripheral lip from entering between the cylinder body and the piston due to the movement of the piston.
  • the master cylinder is provided with a bottomed cylindrical cylinder body having a brake fluid discharge path and a supply path communicating with the reservoir, and is movably disposed in the cylinder body.
  • a piston that forms a pressure chamber that supplies hydraulic pressure to the discharge passage between the cylinder body and a peripheral groove that is provided in a circumferential groove formed in the cylinder body, and the inner circumference is in sliding contact with the piston.
  • a piston seal for sealing between the pressure chamber and the pressure chamber.
  • the piston seal includes an annular base, an inner peripheral lip projecting from the inner peripheral side of the base and slidingly contacting the outer peripheral surface of the piston, and projecting from the outer peripheral side of the base to contact the peripheral groove of the cylinder body.
  • An outer peripheral lip portion that contacts the intermediate lip portion;
  • a connecting portion that extends in the axial direction of the piston seal and connects the inner peripheral lip portion and the intermediate protruding portion is provided between the inner peripheral lip portion and the intermediate protruding portion.
  • a plurality of the connecting portions may be provided separately from each other in the circumferential direction of the base portion.
  • the connecting portion may be formed to extend from the base portion toward the distal end of the intermediate projecting portion.
  • a tapered surface portion may be formed on the opening side of the circumferential groove in the circumferential wall of the circumferential groove on the bottom side of the cylinder body.
  • the front end of the connecting portion may be disposed so as to face the boundary between the tapered surface portion and the wall surface portion on the bottom side of the circumferential groove from the tapered surface portion of the circumferential wall.
  • the connecting portion may be formed to extend at least to the maximum fastening allowance portion of the inner peripheral lip portion.
  • FIG. 3 is a cross-sectional view taken along line AA of FIG. 3A, showing a piston seal of the master cylinder of one embodiment of the present invention.
  • FIG. 3 is a cross-sectional view taken along line BB of FIG.
  • FIG. 3A showing a piston seal of the master cylinder of one embodiment of the present invention.
  • It is a partial expanded sectional view which shows the principal part of the master cylinder of one Embodiment of this invention, Comprising: The state of the movement initial stage of a piston is shown.
  • It is a partial expanded sectional view which shows the principal part of the master cylinder of one Embodiment of this invention, Comprising: The state after FIG. 5A is shown.
  • FIG. 1 An embodiment according to the present invention will be described with reference to the drawings.
  • a force corresponding to an operation amount of a brake pedal (not shown) is introduced via an output shaft of a brake booster (not shown), and brake fluid corresponding to the operation amount of the brake pedal is shown.
  • a reservoir 12 (only a part of which is shown in FIG. 1) for supplying and discharging brake fluid is attached to the master cylinder 11 on the upper side in the vertical direction.
  • the reservoir 12 is directly attached to the master cylinder 11, but the reservoir may be arranged at a position separated from the master cylinder 11, and the reservoir and the master cylinder 11 may be connected by piping. .
  • the master cylinder 11 has a cylinder body 15 made of metal that is formed by processing a single material into a bottomed cylinder having a bottom 13 and a cylinder 14.
  • the cylinder body 15 is disposed on the vehicle in a posture in which the axial direction is along the vehicle front-rear direction.
  • a metal primary piston (piston) 18 is movably disposed on the opening 16 side of the cylinder body 15.
  • a metal secondary piston (piston) 19 is movably disposed on the bottom 13 side of the cylinder body 15 with respect to the primary piston 18.
  • An inner peripheral hole 21 having a bottom surface is formed in the primary piston 18.
  • the secondary piston 19 has an inner peripheral hole 22 having a bottom surface.
  • the master cylinder 11 is a so-called plunger type.
  • the master cylinder 11 is a tandem type master cylinder having the two pistons 18 and 19 as described above.
  • the embodiment is not limited to the application to the tandem type master cylinder, and if it is a plunger type master cylinder, a single type master cylinder in which one piston is arranged in the cylinder body or three or more types.
  • the present invention can be applied to any plunger type master cylinder such as a master cylinder having a plurality of pistons.
  • the cylinder main body 15 has a mounting base portion 23 that protrudes outward in the radial direction of the cylindrical portion 14 (hereinafter referred to as the cylinder radial direction) in the circumferential direction of the cylindrical portion 14 (hereinafter referred to as the cylinder circumferential direction). It is integrally formed at the position.
  • Mounting holes 24 and 25 for mounting the reservoir 12 are formed in the mounting base portion 23.
  • the mounting holes 24 and 25 are shifted in position in the axial direction (hereinafter referred to as the cylinder axis) of the cylindrical portion 14 of the cylinder body 15 in a state where the positions in the cylinder circumferential direction coincide with each other. Is formed at the top.
  • a secondary discharge passage (discharge passage) 26 is formed in the vicinity of the bottom portion 13 on the mounting base portion 23 side of the cylinder portion 14 of the cylinder body 15.
  • a primary discharge path (discharge path) 27 is formed closer to the opening 16 than the secondary discharge path (discharge path) 26.
  • the secondary discharge path 26 and the primary discharge path 27 communicate with a brake cylinder such as a disc brake or a drum brake via a brake pipe, and discharge brake fluid toward the brake cylinder.
  • the secondary discharge passage 26 and the primary discharge passage 27 are formed by shifting the positions in the cylinder axial direction in a state where the positions in the cylinder circumferential direction coincide with each other.
  • the secondary piston 19 is slidably guided to a cylindrical inner surface sliding inner diameter portion 28 centering on the cylinder axis, which is formed on the inner peripheral portion on the bottom 13 side of the cylindrical portion 14 of the cylinder body 15.
  • the primary piston 18 is slidably guided by a cylindrical inner diameter sliding portion 29 centering on the cylinder axis, which is formed on the inner peripheral portion on the opening 16 side of the cylindrical portion 14 of the cylinder body 15.
  • a plurality of, specifically two, annular grooves 30 and 31 are formed in this order from the bottom 13 side in the sliding inner diameter portion 28 by shifting the position in the cylinder axial direction.
  • the sliding inner diameter portion 29 is also formed with a plurality of, specifically two, circumferential grooves 32 and circumferential grooves 33, which are formed in this order from the bottom 13 side, by shifting the position in the cylinder axial direction.
  • These circumferential grooves 30 to 33 have an annular shape in the circumferential direction of the cylinder and are recessed outward in the cylinder radial direction.
  • the circumferential grooves 30 to 33 are all formed by cutting.
  • the circumferential groove 30 on the most bottom 13 side is formed in the vicinity of the mounting hole 24 on the bottom 13 side of the mounting holes 24 and 25.
  • An annular piston seal 35 is disposed in the circumferential groove 30 so as to be held in the circumferential groove 30.
  • the cylinder diameter is such that a communication hole 36 formed from the mounting hole 24 on the bottom portion 13 side is opened in the cylindrical portion 14 on the opening portion 16 side of the sliding inner diameter portion 28 of the cylinder body 15 on the opening portion 16 side.
  • An annular opening groove 37 that is recessed outward in the direction is formed.
  • the opening groove 37 and the communication hole 36 mainly constitute a secondary supply path (supply path) 38 provided in the cylinder body 15 and always communicating with the reservoir 12.
  • the sliding inner diameter portion 28 of the cylinder body 15 has a communication groove (not shown) that opens into the circumferential groove 30 and extends linearly from the circumferential groove 30 toward the bottom portion 13 in the cylinder axial direction. It is formed so as to be recessed.
  • the communication groove communicates the secondary discharge passage 26 and the circumferential groove 30 formed at a position between the bottom portion 13 and the circumferential groove 30 and in the vicinity of the bottom portion 13 through a secondary pressure chamber 68 described later.
  • the circumferential groove 31 is formed in the sliding inner diameter portion 28 of the cylinder body 15 on the side opposite to the circumferential groove 30 of the opening groove 37 in the cylinder axial direction, that is, on the opening 16 side.
  • An annular partition seal 42 is disposed in the circumferential groove 31 so as to be held in the circumferential groove 31.
  • the above-described circumferential groove 32 is formed in the sliding inner diameter portion 29 of the cylinder body 15 in the vicinity of the mounting hole 25 on the opening 16 side.
  • An annular piston seal 45 is disposed in the circumferential groove 32 so as to be held in the circumferential groove 32.
  • a communication hole 46 drilled from the mounting hole 25 on the opening portion 16 side is opened in the cylinder portion 14.
  • An annular opening groove 47 that is recessed outward in the radial direction is formed.
  • the opening groove 47 and the communication hole 46 mainly constitute a primary supply path (supply path) 48 provided in the cylinder body 15 and always communicating with the reservoir 12.
  • an unillustrated communication that opens to the circumferential groove 32 and extends linearly from the circumferential groove 32 toward the bottom 13 side in the cylinder axial direction.
  • the groove is formed to be recessed outward in the cylinder radial direction.
  • the communication groove communicates the primary discharge passage 27 formed at a position near the circumferential groove 31 and the circumferential groove 32 via a primary pressure chamber 85 described later.
  • a circumferential groove 33 is formed in the sliding inner diameter portion 29 of the cylinder body 15 on the side opposite to the circumferential groove 32 of the opening groove 47, that is, on the opening 16 side.
  • An annular partition seal 52 is disposed in the circumferential groove 33 so as to be held in the circumferential groove 33.
  • the secondary piston 19 fitted to the bottom 13 side of the cylinder body 15 has a bottomed cylindrical shape having a cylindrical portion 55 and a bottom portion 56 formed on one side in the axial direction of the cylindrical portion 55. .
  • the inner peripheral hole 22 is formed by the cylindrical portion 55 and the bottom portion 56.
  • the secondary piston 19 is slid on the inner periphery of each of the piston seal 35 and the partition seal 42 provided on the sliding inner diameter portion 28 of the cylinder body 15 with the cylindrical portion 55 disposed on the bottom 13 side of the cylinder body 15. It is movably fitted.
  • An annular step portion 59 having a step shape so as to be positioned radially inward of the outermost diameter portion 58 of the secondary piston 19 at the outer peripheral portion opposite to the bottom portion 56 of the cylindrical portion 55. Is formed.
  • a plurality of ports 60 penetrating in the cylinder radial direction are formed on the bottom 56 side so as to be radially formed at equal intervals in the cylinder circumferential direction.
  • An interval adjustment unit including a secondary piston spring 62 between the secondary piston 19 and the bottom portion 13 of the cylinder body 15 for determining these intervals in a non-braking state without input from a brake pedal (not shown) (right side in FIG. 1).
  • 63 is provided.
  • the interval adjusting portion 63 is connected to the locking member 64 that contacts the bottom portion 13 of the cylinder body 15 and the locking member 64 so as to slide only within a predetermined range, and contacts the bottom portion 56 of the secondary piston 19.
  • a locking member 65 is interposed between the locking members 64 and 65 on both sides.
  • a portion formed by being surrounded by the bottom portion 13 of the cylinder body 15 and the bottom portion 13 side of the cylinder portion 14 and the secondary piston 19 generates a brake fluid pressure and supplies the brake fluid pressure to the secondary discharge passage 26.
  • a secondary pressure chamber (pressure chamber) 68 is formed.
  • the secondary piston 19 forms a secondary pressure chamber 68 that supplies hydraulic pressure to the secondary discharge passage 26 between the secondary piston 19 and the cylinder body 15.
  • the secondary pressure chamber 68 communicates with the secondary supply path 38, that is, the reservoir 12 when the secondary piston 19 is in a position for opening the port 60 into the opening groove 37.
  • the partition seal 42 held in the circumferential groove 31 of the cylinder body 15 is an integrally molded product made of synthetic rubber.
  • the partition seal 42 has a C-shaped one-side shape in a radial section including its center line.
  • the partition seal 42 is in sliding contact with the outer periphery of the secondary piston 19 that moves in the cylinder axial direction, and the outer periphery abuts against the circumferential groove 31 of the cylinder body 15 so that the partition seal 42 of the secondary piston 19 and the cylinder body 15 Always seal position gaps.
  • the piston seal 35 held in the circumferential groove 30 of the cylinder body 15 is an integrally molded product made of synthetic rubber such as EPDM.
  • the piston seal 35 is configured such that the inner periphery is in sliding contact with the outer periphery of the secondary piston 19 that moves in the cylinder axis direction, and the outer periphery is in contact with the circumferential groove 30 of the cylinder body 15.
  • the piston seal 35 can seal between the secondary supply passage 38 and the secondary pressure chamber 68 in a state where the secondary piston 19 has the port 60 positioned on the bottom 13 side of the piston seal 35, that is, the secondary pressure chamber 68. The communication with the secondary supply path 38 and the reservoir 12 can be blocked.
  • the secondary piston 19 slides on the inner circumference of the sliding inner diameter portion 28 of the cylinder body 15 and the piston seal 35 and the partition seal 42 held by the cylinder body 15 and moves to the bottom 13 side.
  • the brake fluid in the secondary pressure chamber 68 is pressurized and supplied from the secondary discharge passage 26 to the brake cylinder on the wheel side.
  • the primary piston 18 fitted to the opening 16 side of the cylinder body 15 includes a first cylindrical portion 71, a bottom portion 72 formed on one side in the axial direction of the first cylindrical portion 71, and a first portion of the bottom portion 72. It has a shape having a second cylindrical portion 73 formed on the opposite side to the first cylindrical portion 71.
  • the inner peripheral hole 21 is formed by the first cylindrical portion 71 and the bottom portion 72 among them.
  • the primary piston 18 has the first cylindrical portion 71 disposed on the secondary piston 19 side in the cylinder body 15 and each of the piston seal 45 and the partition seal 52 provided on the sliding inner diameter portion 29 of the cylinder body 15.
  • the inner periphery is slidably fitted.
  • the output shaft of the brake booster is inserted inside the second cylindrical portion 73, and the bottom portion 72 is pressed by this output shaft.
  • a portion 75 is formed.
  • the step portion 75 is formed with a plurality of ports 76 penetrating in the radial direction on the bottom portion 72 side so as to be radially arranged at equal intervals in the cylinder circumferential direction.
  • the gap adjusting portion 79 includes a locking member 81 that contacts the bottom 72 of the primary piston 18, a locking member 82 that contacts the bottom 56 of the secondary piston 19, and one end fixed to the locking member 81. And a shaft member 83 that slidably supports the stop member 82 only within a predetermined range.
  • the primary piston spring 78 is interposed between the locking members 81 and 82 on both sides.
  • a portion surrounded by the cylinder portion 14 of the cylinder body 15, the primary piston 18 and the secondary piston 19 generates a brake fluid pressure and supplies a brake fluid to the primary discharge passage 27 (primary pressure chamber ( Pressure chamber) 85.
  • the primary piston 18 forms a primary pressure chamber 85 that supplies hydraulic pressure to the primary discharge passage 27 between the secondary piston 19 and the cylinder body 15.
  • the primary pressure chamber 85 is configured to communicate with the primary supply path 48, that is, the reservoir 12 when the primary piston 18 is in a position where the port 76 is opened to the opening groove 47.
  • the partition seal 52 held in the circumferential groove 33 of the cylinder body 15 is the same component as the partition seal 42 and is an integrally molded product made of synthetic rubber.
  • the partition seal 52 has a C-shaped one-side shape in a radial cross section including its center line.
  • the partition seal 52 is in sliding contact with the outer periphery of the primary piston 18 that moves in the cylinder axis direction, and the outer periphery abuts on the circumferential groove 33 of the cylinder body 15 so that the partition seal 52 of the primary piston 18 and the cylinder body 15 Always seal position gaps.
  • the piston seal 45 held in the circumferential groove 32 of the cylinder body 15 is the same component as the piston seal 35 and is an integrally molded product made of synthetic rubber.
  • the piston seal 45 is configured such that the inner circumference is in sliding contact with the outer circumference of the primary piston 18 moving in the cylinder axial direction, and the outer circumference is in contact with the circumferential groove 32 of the cylinder body 15.
  • the piston seal 45 can seal between the primary supply passage 48 and the primary pressure chamber 85 when the primary piston 18 has the port 76 positioned on the bottom 13 side of the piston seal 45, that is, the primary pressure chamber 85. The communication with the primary supply path 48 and the reservoir 12 can be blocked.
  • the primary piston 18 slides on the sliding inner diameter portion 29 of the cylinder body 15 and the inner periphery of the piston seal 45 and the partition seal 52 held by the cylinder body 15 and moves to the bottom 13 side.
  • the brake fluid in the primary pressure chamber 85 is pressurized and supplied from the primary discharge path 27 to the brake cylinder on the wheel side.
  • the secondary side seal structure SS composed of the circumferential groove 30 of the cylinder body 15 and the vicinity thereof, the piston seal 35 and the sliding contact portion of the piston seal 35 of the secondary piston 19, the circumferential groove 32 of the cylinder body 15 and
  • the primary side seal structure SP composed of the vicinity portion, the piston seal 45, and the sliding contact portion of the piston seal 45 of the primary piston 18 has the same structure. Therefore, in the following, these details will be described with reference to FIGS. 2 to 7 mainly by taking the seal structure SP on the primary side as an example.
  • the circumferential groove 32 is a groove bottom portion (bottom portion of the circumferential groove 32) 88 that is on the outermost side in the cylinder radial direction (upper side in FIG. 2) and has a cylindrical surface shape around the cylinder axis.
  • a peripheral wall 89 extending inwardly in the cylinder radial direction along the direction orthogonal to the cylinder axis from the edge of the opening 15 side (right side in FIG. 2) of the cylinder body 15 at the groove bottom 88, and the cylinder body at the groove bottom 88 15 has a peripheral wall 90 extending inwardly in the cylinder radial direction along the direction orthogonal to the cylinder axis from the edge of the bottom 13 side (left side in FIG. 2).
  • the groove bottom portion 88, the peripheral wall 89, and the peripheral wall 90 are formed integrally with the cylinder body 15 and are formed by cutting the cylinder body 15.
  • the peripheral wall 89 has a flat surface portion 89a composed of a flat surface parallel to a plane orthogonal to the cylinder axis, and an R chamfered portion 89b provided on the inner side in the cylinder radial direction than the flat surface portion 89a.
  • the flat surface portion 89a has a constant inner diameter and a constant outer diameter, a constant width in the cylinder radial direction, and has an annular shape centering on the cylinder axis.
  • the R chamfered portion 89b is inclined with respect to the cylinder axial direction so as to be located closer to the opening 16 side (right side in FIG. 2) of the cylinder body 15 from the inner end edge in the cylinder radial direction of the flat surface portion 89a to the inner side in the cylinder radial direction. Is extended.
  • the R chamfered portion 89b has an arc shape in which the cross-sectional shape including the cylinder shaft has a center outside the circumferential groove 32.
  • the R chamfered portion 89b has an annular shape centering on the cylinder axis, and the inner end edge in the cylinder radial direction is closer to the opening 16 than the circumferential groove 32 of the sliding inner diameter portion 29 (right side in FIG. 2). It is connected to the part.
  • the peripheral wall 90 facing the peripheral wall 89 includes a flat surface portion (wall surface portion) 90a formed of a flat surface parallel to the orthogonal surface of the cylinder axis, a tapered surface portion 90b provided on the inner side in the cylinder radial direction than the flat surface portion 90a, and a tapered surface portion.
  • R chamfered portion 90c provided on the inner side in the cylinder radial direction than 90b.
  • the flat surface portion 90a has a constant inner diameter and a constant outer diameter, a constant width in the cylinder radial direction, and has an annular shape centering on the cylinder axis.
  • the tapered surface portion 90b has a tapered shape centered on the cylinder shaft so that the diameter is reduced toward the bottom 13 side (left side in FIG. 2) in the cylinder axial direction from the inner end edge portion of the flat surface portion 90a in the cylinder radial direction. Is extended.
  • the tapered surface portion 90b is formed on the opening side (in the radial direction) of the circumferential groove 32 in the circumferential wall 90 on the bottom 13 side (left side in FIG. 2) of the cylinder body 15 of the circumferential groove 32.
  • a flat surface 90a is formed adjacent to the taper surface 90b on the side of the groove bottom 88 in the cylinder radial direction.
  • the maximum diameter of the tapered surface portion 90 b is larger than the minimum diameter of the flat surface portion 89 a of the peripheral wall 89.
  • the tapered surface portion 90b has an obtuse angle with the flat surface portion 90a.
  • the R chamfered portion 90c is inclined with respect to the cylinder axial direction so as to be located on the bottom 13 side (the left side in FIG. 2) of the cylinder body 15 from the inner end edge in the cylinder radial direction of the tapered surface 90b to the inner side in the cylinder radial direction. Is extended.
  • the R chamfered portion 90 c has an arc shape in which the cross-sectional shape including the cylinder axis has a center outside the circumferential groove 32.
  • the R chamfered portion 90c has an annular shape centering on the cylinder shaft as a whole, and the inner end edge portion in the cylinder radial direction is on the bottom 13 side of the circumferential groove 32 of the sliding inner diameter portion 29 (in FIG. 2). (Left side)
  • the stepped portion 75 formed in the primary piston 18 includes a cylindrical surface portion 75a formed with a constant diameter smaller than the outermost diameter portion 74 having the largest diameter in the primary piston 18, and a cylinder body of the cylindrical surface portion 75a.
  • a tapered surface portion 75b extending so as to increase in diameter toward the opening portion 16 side of the cylinder body 15 from an end edge portion on the opening portion 16 side (right side in FIG. 2) of the cylinder 15 and a cylinder body 15 of the cylindrical surface portion 75a.
  • a taper surface portion 75c extending so as to increase in diameter from the edge on the bottom 13 side (left side in FIG. 2) toward the bottom 13 side of the cylinder body 15.
  • the cylindrical surface portion 75 a, the tapered surface portion 75 b and the tapered surface portion 75 c are formed around the central axis of the primary piston 18 like the outer diameter portion 74.
  • the large diameter side of the tapered surface portion 75b and the large diameter side of the tapered surface portion 75c are connected to the outer diameter portion 74, respectively.
  • the port 76 that always communicates with the primary pressure chamber 85 is formed at a position that spans both the cylindrical surface portion 75a and the tapered surface portion 75b.
  • the end of the port 76 on the bottom 13 side (the left side in FIG. 2) of the cylinder body 15 is positioned on the cylindrical surface portion 75a.
  • the end of the port 76 on the side of the opening 16 of the cylinder body 15 is located on the tapered surface portion 75b.
  • the piston seal 45 disposed in the circumferential groove 32 is an integrally molded product made of synthetic rubber such as EPDM.
  • the piston seal 45 includes an annular plate-like base 101 disposed on the opening 16 side (right side in FIG. 2) of the cylinder main body 15, and the cylinder main body 15 along the axial direction of the base 101 from the inner peripheral end of the base 101.
  • An annular cylindrical inner peripheral lip portion 102 projecting toward the bottom 13 side (left side in FIG. 2), and projecting from the outer peripheral end of the base 101 toward the bottom 13 side (left side in FIG. 2) of the cylinder body 15
  • the outer peripheral lip 103 formed between the outer peripheral lip 103 and the outer peripheral lip 103 and the inner peripheral lip 102 from the base 101 toward the bottom 13 of the cylinder body 15 (left side in FIG.
  • annular cylindrical intermediate projecting portion 104 projecting to the tip.
  • the base portion 101, the inner peripheral lip portion 102, the outer peripheral lip portion 103, and the intermediate protruding portion 104 have the same center axis.
  • This central axis is the central axis of the piston seal 45.
  • the inner peripheral lip portion 102 is in sliding contact with the outer peripheral surface 18a of the primary piston 18 moving in the cylinder axial direction.
  • the outer peripheral lip 103 contacts the peripheral groove 32 of the cylinder body 15.
  • the base 101 has a back surface 101 a, which is the end surface opposite to the protruding direction of the inner peripheral lip 102, the outer peripheral lip 103, and the intermediate protruding portion 104, on the axis orthogonal surface of the piston seal 45. They are parallel.
  • the back surface portion 101 a has a constant inner diameter and a constant outer diameter, a constant width in the radial direction, and has an annular shape centering on the central axis of the piston seal 45.
  • the base 101 has an R chamfered portion 101b formed on the inner side in the radial direction of the back surface portion 101a.
  • An R chamfered portion 101c is formed on the radially outer side of the back surface portion 101a.
  • the central axis of the piston seal 45 is such that the R chamfered portion 101b is positioned closer to the inner peripheral lip portion 102 in the axial direction as it is farther inward in the radial direction from the rear surface portion 101a from the radially inner end edge portion of the rear surface portion 101a. Inclined and extended.
  • the R chamfered portion 101 b has an arc shape in which a cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the base portion 101.
  • the R chamfered portion 101b has an annular shape centering on the central axis of the piston seal 45 as a whole.
  • the R chamfered portion 101c is formed on the central axis of the piston seal 45 so as to be positioned on the outer peripheral lip portion 103 side in the axial direction as the distance from the outer end edge portion in the radial direction of the back surface portion 101a increases radially outward from the back surface portion 101a. It is inclined and extended.
  • the R chamfered portion 101 c has an arc shape in which a cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the base portion 101.
  • the R chamfered portion 101 c has an annular shape centering on the central axis of the piston seal 45 as a whole.
  • the inner peripheral lip portion 102 has a tapered cylindrical shape with a small diameter as a whole as it moves away from the base portion 101 in the axial direction.
  • a reduced diameter inner peripheral surface portion 102a, an enlarged diameter inner peripheral surface portion 102b, and a cylindrical inner peripheral surface portion 102c are formed in this order from the base 101 side in the axial direction.
  • the diameter-reduced inner peripheral surface portion 102a is a piston whose diameter decreases from the inner end edge portion of the R chamfered portion 101b of the base portion 101 in the radial direction of the piston seal 45 in the axial direction.
  • the seal 45 extends in a tapered shape with the central axis as the center.
  • the piston seal is formed so that the enlarged inner peripheral surface portion 102b has a larger diameter (that is, the diameter is increased) from the end edge portion of the reduced inner peripheral surface portion 102a opposite to the base portion 101 in the axial direction. It extends in a tapered shape with the central axis of 45 as the center.
  • the cylindrical inner peripheral surface portion 102 c extends in a cylindrical surface shape centering on the central axis of the piston seal 45 from the end edge portion of the enlarged diameter inner peripheral surface portion 102 b opposite to the base portion 101.
  • a reduced-diameter outer peripheral surface portion 102d and an R chamfered portion 102e are formed in this order from the base 101 side in the axial direction.
  • the reduced-diameter outer peripheral surface portion 102d extends from the base portion 101 in a taper shape centering on the central axis of the piston seal 45 so as to be slightly smaller in diameter in the axial direction.
  • the R chamfered portion 102e extends from the end edge portion of the reduced diameter outer peripheral surface portion 102d opposite to the base portion 101 in an inclined manner with respect to the central axis of the piston seal 45 so that the diameter decreases as the distance from the base portion 101 increases in the axial direction. I'm out.
  • the R chamfered portion 102 e has an arc shape in which the cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the inner peripheral lip portion 102.
  • the R chamfered portion 102e has an annular shape centering on the central axis of the piston seal 45 as a whole.
  • the edge portions of the cylindrical inner peripheral surface portion 102c and the R chamfered portion 102e opposite to the base portion 101 are connected to the distal end surface portion 102f of the inner peripheral lip portion 102 opposite to the base portion 101f.
  • the front end surface portion 102f is parallel to the axis orthogonal surface of the piston seal 45, and has a constant inner diameter and a constant outer diameter, and a constant width in the radial direction of the piston seal 45.
  • the front end surface portion 102 f has an annular shape centering on the central axis of the piston seal 45.
  • the boundary portion between the reduced inner peripheral surface portion 102a and the expanded inner peripheral surface portion 102b is the smallest diameter portion 106 having the smallest inner diameter.
  • a portion between the base portion 101 and the minimum diameter portion 106 is a tip thick portion 107 that becomes thicker as it moves away from the base portion 101 in the axial direction. The position is the thickest.
  • the inner peripheral lip portion 102 is a tapered portion 108 in which the portion of the axially enlarged inner peripheral surface portion 102b becomes thinner as it is separated from the base portion 101, and the portion of the cylindrical inner peripheral surface portion 102c in the axial direction is
  • the tip portion 109 has a constant thickness except for the R chamfered portion 102e.
  • the outer peripheral lip 103 has a tapered cylindrical shape so that the outer diameter of the outer peripheral lip 103 becomes larger as a distance from the base 101 in the axial direction.
  • an enlarged inner peripheral surface portion 103a and a cylindrical inner peripheral surface portion 103b are formed in this order from the base 101 side in the axial direction.
  • the diameter-enlarged inner peripheral surface portion 103a extends from the base portion 101 in a taper shape centering on the central axis of the piston seal 45 so as to increase in diameter (that is, increase in diameter) as it moves away in the axial direction.
  • the cylindrical inner peripheral surface portion 103b extends in a cylindrical surface shape around the central axis of the piston seal 45 from an end edge portion of the enlarged diameter inner peripheral surface portion 103a opposite to the base portion 101.
  • an enlarged outer peripheral surface portion 103c, a cylindrical outer peripheral surface portion 103d, a stepped surface portion 103e, and a cylindrical outer peripheral surface portion 103f are formed in this order from the base 101 side in the axial direction.
  • the diameter-enlarged outer peripheral surface portion 103c extends from the base portion 101 in a tapered shape with the central axis of the piston seal 45 as a center so that the diameter increases as the distance from the base portion 101 increases in the axial direction.
  • the cylindrical outer peripheral surface portion 103 d extends in a cylindrical surface shape centering on the central axis of the piston seal 45 from the end edge portion of the enlarged diameter outer peripheral surface portion 103 c on the side opposite to the base portion 101.
  • the stepped surface portion 103e extends radially inward from the end edge portion of the cylindrical outer peripheral surface portion 103d opposite to the base portion 101 in parallel with the axial orthogonal surface of the piston seal 45.
  • the cylindrical outer peripheral surface portion 103f extends from the inner peripheral edge portion of the step surface portion 103e in a cylindrical surface shape with the central axis of the piston seal 45 as the center.
  • the end portions of the cylindrical inner peripheral surface portion 103 b and the cylindrical outer peripheral surface portion 103 f opposite to the base portion 101 are connected to the distal end surface portion 103 g of the outer peripheral lip portion 103 opposite to the base portion 101 g.
  • the distal end surface portion 103g is parallel to the axial orthogonal surface of the piston seal 45, has a constant inner diameter and a constant outer diameter, has a constant width in the radial direction of the piston seal 45, and is centered on the central axis of the piston seal 45. It has an annular shape.
  • the outer peripheral lip portion 103 is a thin-walled portion 112 where the cylindrical outer peripheral surface portion 103f is thinner in the outer peripheral lip portion 103 than the other main body portion 111 in the radial direction.
  • an enlarged inner peripheral surface portion 104a and an R chamfered portion 104b are formed in this order from the base portion 101 side in the axial direction.
  • the diameter-enlarged inner peripheral surface portion 104a extends from the base portion 101 in a taper shape centering on the central axis of the piston seal 45 so as to become slightly larger in the diameter in the axial direction.
  • the R chamfered portion 104b extends from the end edge portion on the opposite side to the base portion 101 of the enlarged inner peripheral surface portion 104a so as to be inclined with respect to the central axis of the piston seal 45 so as to increase in diameter in the axial direction. ing.
  • the R chamfered portion 104 b has an arc shape in which a cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the intermediate protruding portion 104.
  • the R chamfered portion 104b has an annular shape centering on the central axis of the piston seal 45 as a whole.
  • a reduced diameter outer peripheral surface portion 104c and an R chamfered portion 104d are formed on the outer peripheral side of the intermediate projecting portion 104 in this order from the base 101 side in the axial direction.
  • the reduced-diameter outer peripheral surface portion 104c extends from the base portion 101 in a taper shape centering on the central axis of the piston seal 45 so as to become slightly smaller in diameter in the axial direction.
  • the R chamfered portion 104d extends from the end edge portion of the reduced diameter outer peripheral surface portion 104c opposite to the base portion 101 in an inclined manner with respect to the central axis of the piston seal 45 so as to become smaller in diameter in the axial direction.
  • the R chamfered portion 104 d has an arc shape in which the cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the intermediate protruding portion 104.
  • the R chamfered portion 104d has an annular shape centering on the central axis of the piston seal 45 as a whole.
  • the edge portions on the opposite sides of the base portions 101 of the R chamfered portions 104b and 104d are connected to the tip surface portion 104e on the opposite side of the base portion 101 of the intermediate projecting portion 104.
  • the front end surface portion 104e is parallel to the axis orthogonal surface of the piston seal 45, and has a constant inner diameter and a constant outer diameter, and a constant width in the radial direction of the piston seal 45.
  • the distal end surface portion 104 e also has an annular shape centering on the central axis of the piston seal 45.
  • the tip surface portion 104e of the intermediate projecting portion 104 and the tip surface portion 102f of the inner peripheral lip portion 102 are aligned with each other in the axial direction of the piston seal 45, and the tip surface portion 103g of the outer peripheral lip portion 103 is more base than these. 101 side.
  • the base 101 side of the reduced diameter outer peripheral surface portion 102 d of the inner peripheral lip portion 102 and the base 101 side of the enlarged inner peripheral surface portion 104 a of the intermediate protrusion 104 are connected by a curved surface portion 114.
  • the curved surface portion 114 has an arc shape in which the cross-sectional shape including the central axis of the piston seal 45 has a center in the space between the inner peripheral lip portion 102 and the intermediate protruding portion 104.
  • the enlarged inner peripheral surface portion 103 a of the outer peripheral lip portion 103 and the base 101 side of the reduced outer peripheral surface portion 104 c of the intermediate projecting portion 104 are connected by a curved surface portion 115.
  • the curved surface portion 115 has an arc shape in which the shape of the cross section including the central axis of the piston seal 45 has a center in the space between the outer peripheral lip portion 103 and the intermediate projecting portion 104.
  • the bottom positions of the curved surface portions 114 and 115 constitute the base portion 101. Therefore, in the base 101, the base end portions of the inner peripheral lip portion 102 and the intermediate projecting portion 104 are thick in the axial direction, and the base end portion of the outer peripheral lip portion 103 is thin in the axial direction.
  • a connecting portion 120 that connects the inner peripheral lip portion 102 and the intermediate protruding portion 104 is provided between the inner peripheral lip portion 102 and the intermediate protruding portion 104 as shown in FIG. 4B.
  • the connecting portion 120 has an arc shape centered on the central axis of the piston seal 45, and a plurality of connecting portions 120 are spaced apart at equal intervals in the circumferential direction of the piston seal 45, that is, in the circumferential direction of the base portion 101. (Specifically, 8 places) are formed.
  • a portion where the connecting portion 120 between the inner peripheral lip portion 102 and the intermediate protruding portion 104 is not formed is a slit 121.
  • the slits 121 also have an arc shape centered on the central axis of the piston seal 45, and a plurality of slits 121 are spaced apart at equal intervals in the circumferential direction of the piston seal 45, that is, in the circumferential direction of the base 101 (specifically, eight locations). Is formed.
  • the circumferential length of one slit 121 is longer than the circumferential length of one connecting portion 120. In other words, rather than the fan-shaped central angle formed by connecting one connecting portion 120 and both circumferential ends thereof and the center of the piston seal 45, one slit 121 and both circumferential ends thereof and the center of the piston seal 45 are connected.
  • the central angle of the fan shape formed by tying is larger.
  • the connecting portion 120 has a distal end surface portion 120a opposite to the base portion 101 parallel to the axial orthogonal surface of the piston seal 45, and has a constant inner diameter and a constant outer diameter and a constant width in the radial direction of the piston seal 45. Yes.
  • the connecting portion 120 has a piston seal 45 that passes through the center of the connecting portion 120 such that the distance between the pair of side surface portions 120b, 120b on both sides in the circumferential direction of the arcuate tip surface portion 120a decreases as the distance from the base portion 101 increases. It is inclined in line symmetry with respect to a line parallel to the central axis.
  • the connecting portion 120 is integrated with the reduced diameter outer peripheral surface portion 102d of the inner peripheral lip portion 102, the enlarged inner peripheral surface portion 104a of the intermediate projecting portion 104, and the curved surface portion 114 therebetween. . More specifically, the connecting portion 120 is integrated with the curved surface portion 114 over the entire length of the piston seal 45 in the axial direction and the radial direction, and the piston 120 is also connected to the reduced diameter outer peripheral surface portion 102d and the expanded inner peripheral surface portion 104a. The seal 45 is integrated over almost the entire length in the axial direction.
  • the connecting portion 120 is formed so as to extend in the axial direction of the piston seal 45, and extends from the base portion 101 along the axial direction of the piston seal 45 in the distal direction of the protrusion of the intermediate protruding portion 104 and the inner peripheral lip portion 102. Is formed.
  • the front end surface portion 120a of the connecting portion 120 extends to the opposite side of the base portion 101 from the minimum diameter portion 106 of the inner peripheral lip portion 102, and extends to an intermediate position in the axial direction of the cylindrical inner peripheral surface portion 102c.
  • FIG. 2 it is incorporated in the circumferential groove 32 of the cylinder body 15 and properly contacts the axial intermediate position of the cylindrical surface portion 75 a of the step portion 75 of the primary piston 18 and the circumferential groove 32.
  • the piston seal 45 in the basic state (non-braking state before the brake pedal is operated) separated from the peripheral wall 90 on the bottom 13 side (left side in FIG. 2) will be described.
  • the base 101 of the piston seal 45 When in this basic state, the base 101 of the piston seal 45 is positioned closest to the opening 16 side (right side in FIG. 2) of the cylinder body 15 in a posture parallel to the plane perpendicular to the cylinder axis. Therefore, the base portion 101 is disposed to face the peripheral wall 89 of the peripheral groove 32, and abuts against the flat surface portion 89a of the peripheral wall 89 at the back surface portion 101a. Further, the inner peripheral lip portion 102 located on the innermost peripheral side contacts the cylindrical surface portion 75a of the stepped portion 75 of the outer peripheral surface 18a of the primary piston 18 at the inner peripheral portion thereof. At this time, the inner peripheral lip portion 102 has a reduced diameter inner peripheral surface portion 102a shown in FIGS.
  • the inner peripheral lip portion 102 comes into contact with the cylindrical surface portion 75a with a tightening margin, and at this time, the minimum diameter portion 106 having the smallest inner diameter is the maximum tightening margin portion where the tightening margin with respect to the cylindrical surface portion 75a is maximized. It becomes. Then, the connecting portion 120 is formed so as to extend to the minimum diameter portion 106 serving as the maximum fastening allowance portion.
  • the piston seal 45 when in the basic state, the piston seal 45 is such that the cylindrical inner peripheral surface portion 102c and a part of the enlarged inner peripheral surface portion 102b on the cylindrical inner peripheral surface portion 102c side are separated from the cylindrical surface portion 75a of the piston 18 in the cylinder radial direction.
  • a gap portion 125 is formed between the cylindrical surface portion 75a.
  • the gap portion 125 has an annular shape centered on the central axis of the piston seal 45, and extends to the bottom 13 side (left side in FIG. 2) in the cylinder axis direction.
  • the connecting portion 120 extends to the opposite side of the base portion 101 from the end portion position of the gap portion 125 on the base portion 101 side.
  • the outermost peripheral lip 103 of the piston seal 45 is in contact with the groove bottom 88 of the peripheral groove 32 at the outermost cylindrical outer peripheral surface 103d.
  • the intermediate projecting portion 104 is in a state similar to the natural state, and the tip surface portion 104e is parallel to the orthogonal surface of the cylinder axis.
  • the intermediate projecting portion 104 has a length equivalent to that of the inner peripheral lip portion 102 and extends to the bottom 13 side (left side in FIG. 2) of the cylinder body 15 from the outer peripheral lip portion 103.
  • the intermediate projecting portion 104 when in the basic state, has the tip end surface portion 104e entirely aligned with the flat surface portion 90a of the peripheral wall 90 of the peripheral groove 32 in the cylinder radial direction.
  • the intermediate projecting portion 104 is arranged so as to face the flat surface portion 90a in the cylinder axial direction and be able to contact the flat surface portion 90a.
  • the intermediate protrusion 104 is separated from the peripheral wall 90 including the flat surface portion 90a in the cylinder axial direction.
  • the inner peripheral lip portion 102 has a front end surface portion 102f which is connected to the tapered surface portion 90b and the R chamfered portion 90c of the peripheral wall 90 of the peripheral groove 32 and the tapered surface portion 75c of the step portion 75 of the primary piston 18
  • the radial position is matched.
  • the inner peripheral lip portion 102 is disposed so as to face the tapered surface portion 90b, the R chamfered portion 90c, and the tapered surface portion 75c.
  • the inner peripheral lip portion 102 is separated in the cylinder axial direction from the peripheral wall 90 including the tapered surface portion 90b and the R chamfered portion 90c, and is also separated in the cylinder axial direction from the tapered surface portion 75c.
  • the tip end surface portion 102f of the inner peripheral lip portion 102 does not overlap the position in the cylinder radial direction on the flat surface portion 90a of the peripheral wall 90.
  • the front end surface portion 120a of the connecting portion 120 is cylinder-bound at a boundary portion 127 between the tapered surface portion 90b of the peripheral wall 90 of the peripheral groove 32 and the flat surface portion 90a on the groove bottom portion 88a side.
  • the radial position is matched.
  • the front end surface portion 120a is disposed so as to face the boundary portion 127 in the cylinder axial direction.
  • the distal end surface portion 120a of the connecting portion 120 is aligned with the cylinder radial position on both the tapered surface portion 90b and the flat surface portion 90a, and faces both the tapered surface portion 90b and the flat surface portion 90a in the cylinder axial direction. Has been placed.
  • the inner peripheral portion of the lip portion 102 and the base portion 101 is at the position of the cylindrical surface portion 75 a of the step portion 75 of the primary piston 18, and the inner peripheral portion of the base portion 101 overlaps a part of the port 76 with the position in the cylinder axial direction. It is configured as follows.
  • the inner peripheral lip portion 102 When the primary piston 18 further moves to the bottom 13 side of the cylinder body 15 (left side in FIGS. 5A and 5B), the inner peripheral lip portion 102 receives a force that moves together with the primary piston 18, but it hits the peripheral wall 90 of the peripheral groove 32.
  • the intermediate projecting portion 104 that is in contact pulls the inner peripheral lip portion 102 connected by the connecting portion 120 to suppress the movement thereof.
  • the inner peripheral lip portion 102 is prevented from entering the gap between the stepped portion 75 of the primary piston 18 and the sliding inner diameter portion 29 of the cylinder body 15 and being caught therein.
  • the piston seal 45 is in contact with the flat surface portion 90a of the peripheral wall 90 and is pressed by the tapered surface portion 75b against the intermediate protrusion portion 104 that is substantially in a stopped state.
  • 101b moves to the bottom 13 side (the left side in FIGS. 5A and 5B) of the cylinder body 15, but the piston seal 45 has the tip surface portion 104e side of the intermediate protrusion 104 centered on the R chamfered portion 101b of the base 101.
  • a moment in the direction of movement toward the groove bottom 88 is generated.
  • the intermediate projecting portion 104 slightly rotates so that the front end surface portion 104 e approaches the groove bottom portion 88.
  • the inner peripheral lip portion 102 connected to the intermediate projecting portion 104 by the connecting portion 120 is pulled by the intermediate projecting portion 104 and moved integrally with the tapered surface portion 90b while being prevented from contacting the peripheral wall 90. Then, it is spaced apart from the stepped portion 75 of the primary piston 18 in the radial direction and abuts against the flat surface portion 90 a side of the tapered surface portion 90 b, and is positioned radially outward from the sliding inner diameter portion 29 of the cylinder body 15. Thereby, it is possible to further suppress the inner peripheral lip portion 102 from entering the gap between the step portion 75 of the primary piston 18 and the sliding inner diameter portion 29 of the cylinder body 15.
  • the piston seal 45 moves while maintaining the state where the intermediate protrusion 104 is in contact with the flat surface portion 90 a of the peripheral wall 90. Is regulated. For this reason, the piston seal 45 rides on the tapered surface portion 75 b of the stepped portion 75, crosses the port 76, closes the port 76, and blocks communication between the primary pressure chamber 85 and the primary supply path 48.
  • the piston seal 45 includes the primary pressure chamber 85 and the primary supply passage 48 in a range including this position and the position where the primary piston 18 is located on the bottom 13 side of the cylinder body 15 (left side in FIGS. 5A and 5B).
  • the primary pressure chamber 85 is sealed. In this state, basically, the hydraulic pressure in the primary pressure chamber 85 is higher than the hydraulic pressure in the primary replenishment passage 48, which is atmospheric pressure, and the brake fluid in the primary pressure chamber 85 flows into the primary discharge passage shown in FIG. 27 to the wheel-side brake cylinder.
  • the piston seal 45 After the port 76 is closed, when the primary piston 18 further moves to the bottom 13 side of the cylinder body 15 (left side in FIGS. 5A and 5B), the piston seal 45 has an outer diameter portion with the base 101 overcoming the tapered surface portion 75b. Get on 74. At the same time, the inner peripheral lip portion 102 rides on the tapered surface portion 75 b, and then the inner peripheral lip portion 102 rides on the outer diameter portion 74. The piston seal 45 moves toward the peripheral wall 89 in the peripheral groove 32 due to the increase in the hydraulic pressure in the primary pressure chamber 85 described above. Thereby, the intermediate
  • the hydraulic pressure in the primary pressure chamber 85 becomes negative, and the hydraulic pressure in the primary pressure chamber 85 becomes lower than the hydraulic pressure in the primary supply path 48, which is atmospheric pressure. Then, the negative pressure in the primary pressure chamber 85 is deformed so that the outer peripheral lip 103 side of the base 101 of the piston seal 45 is separated from the peripheral wall 89 and the outer peripheral lip 103 is separated from the groove bottom 88. Let As a result, a gap is formed between the circumferential groove 32 and the piston seal 45, and the brake fluid is replenished from the primary replenishment path 48 to the primary pressure chamber 85 through the flow path of this gap. Thereby, the hydraulic pressure in the primary pressure chamber 85 can be returned from the negative pressure state to the atmospheric pressure.
  • ⁇ max is an allowable displacement with which the inner peripheral lip portion 102 is pushed down in the inner diameter direction
  • W is a radial reaction force applied per width of the slit 121 of the inner peripheral lip portion 102 when sliding on the tapered surface portion 75b.
  • b is the axial length of the inner peripheral lip 102
  • H is the radial height of the inner peripheral lip 102
  • D is the primary piston.
  • E is the Young's modulus.
  • a piston seal that is in sliding contact with the piston is disposed in a circumferential groove of the cylinder body.
  • an annular base, an inner peripheral lip projecting from the inner peripheral side of the base and slidingly contacting the outer peripheral surface of the piston, and projecting from the outer peripheral side of the base project against the circumferential groove of the cylinder body.
  • a cup-type seal having an annular base portion, an inner peripheral lip portion and an outer peripheral lip portion protruding from the inner and outer periphery thereof is provided in the annular groove of the piston, A sliding ring that slides in the cylinder hole is provided between the cup-shaped seal of the annular groove and the cylinder hole of the cylinder body.
  • the piston seal moves together with the piston, and the inner peripheral lip portion may enter the gap between the piston and the cylinder body.
  • the connecting portion 120 that connects the inner peripheral lip portion 102 and the intermediate protruding portion 104 to the piston seal 45 provided in the peripheral groove 32 of the cylinder body 15 is provided. Therefore, even if the inner peripheral lip portion 102 tries to move together with the primary piston 18, the intermediate protrusion 104 that contacts the peripheral wall 90 of the peripheral groove 32 pulls the inner peripheral lip portion 102 and suppresses the movement. Therefore, it is possible to suppress the inner peripheral lip portion 102 from entering the gap between the primary piston 18 and the cylinder body 15, and it is possible to suppress the influence on the piston seal 45 due to the movement of the primary piston 18.
  • a thick portion is formed in the base portion.
  • the inner peripheral lip portion and the outer peripheral lip portion do not slidably contact the cylinder body or the piston.
  • the meat portion does not contribute to the influence on the cup-type seal due to the movement of the piston.
  • connecting portion 120 is formed to extend from the base portion 101 toward the distal end of the intermediate projecting portion 104, molding becomes easy.
  • the tip of the connecting portion 120 is disposed so as to face the boundary portion 127 between the tapered surface portion 90b and the flat surface portion 90a. For this reason, the inner peripheral lip part 102 can be made to oppose the taper surface part 90b, and the distance of the inner peripheral lip part 102 and the peripheral wall 90 is securable.
  • the connecting portion 120 is formed to extend to the minimum diameter portion 106 that is the maximum fastening allowance portion of the inner peripheral lip portion 102. For this reason, the rigidity of the minimum diameter portion 106 can be increased by the connecting portion 120, and the surface pressure of the inner peripheral lip portion 102 to the primary piston 18 can be increased.
  • the piston seal 45 may be partially changed as shown in FIGS. That is, as shown in FIG. 6, the projection length of the inner peripheral lip portion 102 from the base 101 is shorter than the intermediate projection portion 104, or the connecting portion 120 is shortened to reduce the minimum diameter portion of the enlarged inner peripheral surface portion 102 b. It can be formed up to the position on the 106 side. Even when the connecting portion 120 is shortened, it is preferable that it extends at least to the position of the minimum diameter portion 106.
  • the connecting portion 120 is extended to the position of the front end surface portion 102f of the inner peripheral lip portion 102 and the front end surface portion 104e of the intermediate projecting portion 104, or the front end portion of the inner peripheral lip portion 102 having a substantially constant thickness. 109, or a slit 130 penetrating in the radial direction in the thin-walled portion 112 of the outer peripheral lip 103, or an intermediate length of the inner peripheral lip 102 that protrudes from the base 101 shorter than the intermediate protruding portion 104. It is also possible to form a slit 131 penetrating in the radial direction at the end of the protrusion 104 opposite to the base 101.
  • the connecting portion 120 When the connecting portion 120 is extended to the positions of the front end surface portion 102f of the inner peripheral lip portion 102 and the front end surface portion 104e of the intermediate projecting portion 104, when the front end surface portions 102f and 104e are offset in the axial direction, the front end of the connecting portion 120
  • the surface portion 120a has a tapered surface shape.
  • the slit 130 penetrating in the radial direction is formed in the thin portion 112 of the outer peripheral lip 103, or the slit 131 is formed at the end opposite to the base 101 of the intermediate projecting portion 104 as described above.
  • a wider flow path can be formed between the peripheral wall 89 and the piston seal 45, and the brake fluid in the primary supply path 48 can be smoothly supplied to the primary pressure chamber 85.
  • the primary-side seal structure portion SP has been described in detail as an example, but the secondary-side seal structure portion SS has the same structure, and thus the same effect can be achieved. Similar changes are possible.
  • the above embodiment is provided with a bottomed cylindrical cylinder body having a brake fluid discharge path and a replenishment path communicating with the reservoir, and is movably disposed in the cylinder body.
  • a piston that forms a pressure chamber that supplies hydraulic pressure to the discharge path, and an inner circumference that is provided in a circumferential groove formed in the cylinder body and that is in sliding contact with the piston to seal between the supply path and the pressure chamber
  • a piston seal that protrudes from the outer peripheral side of the base, and an annular base, an inner peripheral lip that protrudes from the inner peripheral side of the base and slidably contacts the outer peripheral surface of the piston, An outer peripheral lip portion that comes into contact with the peripheral groove of the cylinder body, and an intermediate protruding portion that protrudes from between the inner peripheral lip portion and the outer peripheral lip portion of the base portion to beyond the outer peripheral lip portion.
  • a connecting portion is provided between the inner peripheral lip portion and the intermediate projecting portion so as to extend in the axial direction of the piston seal, and connects the inner peripheral lip portion and the intermediate projecting portion. It is characterized by being.
  • the piston seal provided in the circumferential groove of the cylinder body is provided with a connecting portion that connects the inner peripheral lip portion and the intermediate protruding portion, even if the inner peripheral lip portion tries to move together with the piston, The intermediate protrusion that contacts the peripheral wall of the peripheral groove pulls the inner peripheral lip and suppresses the movement thereof. Therefore, it is possible to suppress the inner peripheral lip portion from entering between the cylinder body and the piston due to the movement of the piston.
  • connecting portion is formed to extend from the base portion toward the distal end of the intermediate projecting portion, molding is facilitated.
  • a tapered surface portion is formed on the opening side of the circumferential groove on the circumferential wall on the bottom side of the cylinder body of the circumferential groove, and the tip of the coupling portion is formed by the tapered surface portion and the tapered surface portion of the circumferential wall. Since it arrange
  • the connecting portion is formed to extend to at least the maximum tightening margin portion of the inner peripheral lip portion, the rigidity of the maximum tightening margin portion can be increased by the connecting portion, and the inner peripheral lip portion to the piston can be increased.
  • the surface pressure can be increased.
  • the master cylinder of the present invention it is possible to prevent the inner peripheral lip from entering between the cylinder body and the piston due to the movement of the piston.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Transportation (AREA)
  • Transmission Of Braking Force In Braking Systems (AREA)
  • Sealing Devices (AREA)
  • Sealing With Elastic Sealing Lips (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

A piston seal comprising: an annular base part; an inner peripheral lip part which protrudes from an inner peripheral side of the base part, and is in sliding contact with an outer peripheral surface of a piston; an outer peripheral lip part which protrudes from an outer peripheral side of the base part, and is in contact with a peripheral groove of a cylinder main body; and a intermediate protruding part which protrudes from between the inner peripheral lip part and the outer peripheral lip part of the base part, further than the outer peripheral lip part. A linking part is provided between the inner peripheral lip part and the intermediate protruding part, is formed so as to extend in an axial direction of the piston seal, and links the inner peripheral lip part and the intermediate protruding part.

Description

マスタシリンダMaster cylinder
　本発明は、車両の制動用シリンダへ液圧を供給するマスタシリンダに関する。
　本願は、２０１２年１０月３１日に、日本に出願された特願２０１２－２４１１９８号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a master cylinder that supplies hydraulic pressure to a brake cylinder of a vehicle.
This application claims priority based on Japanese Patent Application No. 2012-241198 filed in Japan on October 31, 2012, the contents of which are incorporated herein by reference.
　マスタシリンダには、シリンダ本体の周溝内に内周リップ部を有するピストンシールを配設し、このピストンシールの内周リップ部をピストンに摺接させるものがある（例えば特許文献１参照）。 Some master cylinders are provided with a piston seal having an inner peripheral lip portion in a circumferential groove of a cylinder body, and the inner peripheral lip portion of the piston seal is in sliding contact with the piston (see, for example, Patent Document 1).
　また、マスタシリンダには、ピストンの環状溝に、カップ型シールとシリンダ本体に摺接する摺動リングとを設けたものがある（例えば特許文献２参照）。 Further, some master cylinders are provided with a cup-shaped seal and a sliding ring that is in sliding contact with the cylinder body in an annular groove of a piston (see, for example, Patent Document 2).
特開２００６－１２３８７９号公報JP 2006-123879 A 特開平９－１３６６４１号公報JP-A-9-136641
　特許文献１に記載のマスタシリンダのように、シリンダ本体の周溝内にピストンシールを配設し、このピストンシールに対してピストンが摺接する構造であると、ピストンの移動によってピストンシールの内周リップ部がシリンダ本体とピストンとの間に入り込んでしまう可能性がある。 As in the master cylinder described in Patent Document 1, when the piston seal is disposed in the circumferential groove of the cylinder body and the piston is in sliding contact with the piston seal, the inner circumference of the piston seal is moved by the movement of the piston. The lip portion may enter between the cylinder body and the piston.
　本発明は、ピストンの移動によるシリンダ本体とピストンとの間への内周リップ部の入り込みを抑制可能なマスタシリンダを提供する。 The present invention provides a master cylinder capable of suppressing the inner peripheral lip from entering between the cylinder body and the piston due to the movement of the piston.
　本発明の第１の態様によれば、マスタシリンダは、ブレーキ液の吐出路とリザーバに連通する補給路とを有する有底筒状のシリンダ本体と、該シリンダ本体内に移動可能に配設され、該シリンダ本体との間に前記吐出路へ液圧を供給する圧力室を形成するピストンと、前記シリンダ本体に形成された周溝内に設けられ内周が前記ピストンに摺接して前記補給路と前記圧力室との間を密封するピストンシールとを有する。前記ピストンシールは、円環状の基部と、該基部の内周側から突出してピストンの外周面に摺接する内周リップ部と、前記基部の外周側から突出して前記シリンダ本体の前記周溝に当接する外周リップ部と、前記基部の前記内周リップ部と前記外周リップ部との間から該外周リップ部よりも先まで突出する中間突出部と、を備える。前記内周リップ部と前記中間突出部との間に、前記ピストンシールの軸方向に延びて形成され、前記内周リップ部と前記中間突出部とを連結する連結部が設けられる。 According to the first aspect of the present invention, the master cylinder is provided with a bottomed cylindrical cylinder body having a brake fluid discharge path and a supply path communicating with the reservoir, and is movably disposed in the cylinder body. A piston that forms a pressure chamber that supplies hydraulic pressure to the discharge passage between the cylinder body and a peripheral groove that is provided in a circumferential groove formed in the cylinder body, and the inner circumference is in sliding contact with the piston. And a piston seal for sealing between the pressure chamber and the pressure chamber. The piston seal includes an annular base, an inner peripheral lip projecting from the inner peripheral side of the base and slidingly contacting the outer peripheral surface of the piston, and projecting from the outer peripheral side of the base to contact the peripheral groove of the cylinder body. An outer peripheral lip portion that contacts the intermediate lip portion; A connecting portion that extends in the axial direction of the piston seal and connects the inner peripheral lip portion and the intermediate protruding portion is provided between the inner peripheral lip portion and the intermediate protruding portion.
　前記連結部は、前記基部の周方向にそれぞれ離間して複数設けられていてもよい。
　前記連結部は、前記基部から前記中間突出部の先端方向に延びて形成されていてもよい。 A plurality of the connecting portions may be provided separately from each other in the circumferential direction of the base portion.
The connecting portion may be formed to extend from the base portion toward the distal end of the intermediate projecting portion.
　本発明の第２の態様によれば、前記周溝の前記シリンダ本体の底部側の周壁における前記周溝の開口側には、テーパ面部が形成されてもよい。前記連結部の先端は、前記テーパ面部と、前記周壁の前記テーパ面部より前記周溝の底部側の壁面部との境界部に向かい合うように配置されていてもよい。 According to the second aspect of the present invention, a tapered surface portion may be formed on the opening side of the circumferential groove in the circumferential wall of the circumferential groove on the bottom side of the cylinder body. The front end of the connecting portion may be disposed so as to face the boundary between the tapered surface portion and the wall surface portion on the bottom side of the circumferential groove from the tapered surface portion of the circumferential wall.
　前記連結部は、少なくとも前記内周リップ部の最大締め代部位まで延びて形成されていてもよい。 The connecting portion may be formed to extend at least to the maximum fastening allowance portion of the inner peripheral lip portion.
　上記したマスタシリンダによれば、ピストンの移動によるシリンダ本体とピストンとの間への内周リップ部の入り込みを抑制することが可能となる。 According to the master cylinder described above, it is possible to suppress the inner peripheral lip from entering between the cylinder body and the piston due to the movement of the piston.
本発明に係る一実施形態のマスタシリンダを示す断面図である。It is sectional drawing which shows the master cylinder of one Embodiment which concerns on this invention. 本発明の一実施形態のマスタシリンダの要部を示す部分拡大断面図であってピストンが基本位置にある状態を示すものである。It is a partial expanded sectional view which shows the principal part of the master cylinder of one Embodiment of this invention, Comprising: The state which has a piston in a basic position is shown. 本発明の一実施形態のマスタシリンダのピストンシールを示す正面図である。It is a front view which shows the piston seal of the master cylinder of one Embodiment of this invention. 本発明の一実施形態のマスタシリンダのピストンシールを示す側面図である。It is a side view which shows the piston seal of the master cylinder of one Embodiment of this invention. 本発明の一実施形態のマスタシリンダのピストンシールを示すもので、図３ＡのＡ－Ａ断面図である。FIG. 3 is a cross-sectional view taken along line AA of FIG. 3A, showing a piston seal of the master cylinder of one embodiment of the present invention. 本発明の一実施形態のマスタシリンダのピストンシールを示すもので、図３ＡのＢ－Ｂ断面図である。FIG. 3 is a cross-sectional view taken along line BB of FIG. 3A, showing a piston seal of the master cylinder of one embodiment of the present invention. 本発明の一実施形態のマスタシリンダの要部を示す部分拡大断面図であって、ピストンの移動初期の状態を示すものである。It is a partial expanded sectional view which shows the principal part of the master cylinder of one Embodiment of this invention, Comprising: The state of the movement initial stage of a piston is shown. 本発明の一実施形態のマスタシリンダの要部を示す部分拡大断面図であって、図５Ａの後の状態を示すものである。It is a partial expanded sectional view which shows the principal part of the master cylinder of one Embodiment of this invention, Comprising: The state after FIG. 5A is shown. ピストンシールの変形例を示す断面図である。It is sectional drawing which shows the modification of a piston seal. ピストンシールの変形例を示す断面図である。It is sectional drawing which shows the modification of a piston seal.
　本発明に係る一実施形態を図面を参照して説明する。図１に示す本実施形態のマスタシリンダ１１は、図示略のブレーキペダルの操作量に応じた力が図示略のブレーキブースタの出力軸を介して導入され、ブレーキペダルの操作量に応じたブレーキ液圧を発生させる。このマスタシリンダ１１には、鉛直方向上側にブレーキ液を給排するリザーバ１２（図１において一部のみ図示）が取り付けられている。なお、本実施形態においては、マスタシリンダ１１に直接リザーバ１２を取り付けているが、マスタシリンダ１１から離間した位置にリザーバを配し、リザーバとマスタシリンダ１１とを配管で接続するようにしても良い。 An embodiment according to the present invention will be described with reference to the drawings. In the master cylinder 11 of this embodiment shown in FIG. 1, a force corresponding to an operation amount of a brake pedal (not shown) is introduced via an output shaft of a brake booster (not shown), and brake fluid corresponding to the operation amount of the brake pedal is shown. Generate pressure. A reservoir 12 (only a part of which is shown in FIG. 1) for supplying and discharging brake fluid is attached to the master cylinder 11 on the upper side in the vertical direction. In this embodiment, the reservoir 12 is directly attached to the master cylinder 11, but the reservoir may be arranged at a position separated from the master cylinder 11, and the reservoir and the master cylinder 11 may be connected by piping. .
　マスタシリンダ１１は、底部１３と筒部１４とを有する有底筒状に一つの素材から加工されて形成される金属製のシリンダ本体１５を有している。シリンダ本体１５は、軸線方向が車両前後方向に沿う姿勢で車両に配置される。このシリンダ本体１５の開口部１６側には、金属製のプライマリピストン（ピストン）１８が移動可能に配置されている。また、シリンダ本体１５のプライマリピストン１８よりも底部１３側には、同じく金属製のセカンダリピストン（ピストン）１９が移動可能に配置されている。プライマリピストン１８には底面を有する内周孔２１が形成されている。セカンダリピストン１９には底面を有する内周孔２２が形成されている。マスタシリンダ１１は、いわゆるプランジャ型である。また、マスタシリンダ１１は、上記したように２つのピストン１８，１９を有するタンデムタイプのマスタシリンダである。なお、実施形態は、上記タンデムタイプのマスタシリンダへの適用に限られるものではなく、プランジャ型のマスタシリンダであれば、シリンダ本体に１つのピストンを配したシングルタイプのマスタシリンダや、３つ以上のピストンを有するマスタシリンダ等のいかなるプランジャ型のマスタシリンダにも適用できる。 The master cylinder 11 has a cylinder body 15 made of metal that is formed by processing a single material into a bottomed cylinder having a bottom 13 and a cylinder 14. The cylinder body 15 is disposed on the vehicle in a posture in which the axial direction is along the vehicle front-rear direction. A metal primary piston (piston) 18 is movably disposed on the opening 16 side of the cylinder body 15. Similarly, a metal secondary piston (piston) 19 is movably disposed on the bottom 13 side of the cylinder body 15 with respect to the primary piston 18. An inner peripheral hole 21 having a bottom surface is formed in the primary piston 18. The secondary piston 19 has an inner peripheral hole 22 having a bottom surface. The master cylinder 11 is a so-called plunger type. The master cylinder 11 is a tandem type master cylinder having the two pistons 18 and 19 as described above. The embodiment is not limited to the application to the tandem type master cylinder, and if it is a plunger type master cylinder, a single type master cylinder in which one piston is arranged in the cylinder body or three or more types. The present invention can be applied to any plunger type master cylinder such as a master cylinder having a plurality of pistons.
　シリンダ本体１５には、筒部１４の径方向（以下、シリンダ径方向と称す）の外側に突出する取付台部２３が、筒部１４の円周方向（以下、シリンダ周方向と称す）における所定位置に一体に形成されている。この取付台部２３には、リザーバ１２を取り付けるための取付穴２４，２５が形成されている。なお、本実施形態においては、取付穴２４，２５は、互いにシリンダ周方向における位置を一致させた状態で、シリンダ本体１５の筒部１４の軸線（以下、シリンダ軸と称す）方向における位置をずらして上部に形成されている。 The cylinder main body 15 has a mounting base portion 23 that protrudes outward in the radial direction of the cylindrical portion 14 (hereinafter referred to as the cylinder radial direction) in the circumferential direction of the cylindrical portion 14 (hereinafter referred to as the cylinder circumferential direction). It is integrally formed at the position. Mounting holes 24 and 25 for mounting the reservoir 12 are formed in the mounting base portion 23. In the present embodiment, the mounting holes 24 and 25 are shifted in position in the axial direction (hereinafter referred to as the cylinder axis) of the cylindrical portion 14 of the cylinder body 15 in a state where the positions in the cylinder circumferential direction coincide with each other. Is formed at the top.
　シリンダ本体１５の筒部１４の取付台部２３側には、底部１３の近傍にセカンダリ吐出路（吐出路）２６が形成されている。セカンダリ吐出路（吐出路）２６よりも開口部１６側にプライマリ吐出路（吐出路）２７が形成されている。これらセカンダリ吐出路２６およびプライマリ吐出路２７は、図示は略すが、ブレーキ配管を介してディスクブレーキやドラムブレーキ等の制動用シリンダに連通しており、制動用シリンダに向けてブレーキ液を吐出する。なお、本実施形態においては、これらセカンダリ吐出路２６およびプライマリ吐出路２７は、互いにシリンダ周方向における位置を一致させた状態でシリンダ軸方向における位置をずらして形成されている。 A secondary discharge passage (discharge passage) 26 is formed in the vicinity of the bottom portion 13 on the mounting base portion 23 side of the cylinder portion 14 of the cylinder body 15. A primary discharge path (discharge path) 27 is formed closer to the opening 16 than the secondary discharge path (discharge path) 26. Although not shown, the secondary discharge path 26 and the primary discharge path 27 communicate with a brake cylinder such as a disc brake or a drum brake via a brake pipe, and discharge brake fluid toward the brake cylinder. In the present embodiment, the secondary discharge passage 26 and the primary discharge passage 27 are formed by shifting the positions in the cylinder axial direction in a state where the positions in the cylinder circumferential direction coincide with each other.
　セカンダリピストン１９は、シリンダ本体１５の筒部１４の底部１３側の内周部に形成された、シリンダ軸を中心とする円筒面状の摺動内径部２８に摺動可能に案内される。プライマリピストン１８は、シリンダ本体１５の筒部１４の開口部１６側の内周部に形成された、シリンダ軸を中心とする円筒面状の摺動内径部２９に摺動可能に案内される。 The secondary piston 19 is slidably guided to a cylindrical inner surface sliding inner diameter portion 28 centering on the cylinder axis, which is formed on the inner peripheral portion on the bottom 13 side of the cylindrical portion 14 of the cylinder body 15. The primary piston 18 is slidably guided by a cylindrical inner diameter sliding portion 29 centering on the cylinder axis, which is formed on the inner peripheral portion on the opening 16 side of the cylindrical portion 14 of the cylinder body 15.
　摺動内径部２８には、シリンダ軸方向における位置をずらして複数、具体的には２カ所の、いずれも円環状をなす周溝３０、周溝３１が底部１３側からこの順に形成されている。また、摺動内径部２９にも、シリンダ軸方向における位置をずらして複数、具体的には２カ所の、いずれも円環状をなす周溝３２、周溝３３が底部１３側からこの順に形成されている。これら周溝３０～３３は、シリンダ周方向に環状をなしてシリンダ径方向外側に凹む形状をなしている。周溝３０～３３は、いずれも全体が切削加工により形成されている。 A plurality of, specifically two, annular grooves 30 and 31 are formed in this order from the bottom 13 side in the sliding inner diameter portion 28 by shifting the position in the cylinder axial direction. . In addition, the sliding inner diameter portion 29 is also formed with a plurality of, specifically two, circumferential grooves 32 and circumferential grooves 33, which are formed in this order from the bottom 13 side, by shifting the position in the cylinder axial direction. ing. These circumferential grooves 30 to 33 have an annular shape in the circumferential direction of the cylinder and are recessed outward in the cylinder radial direction. The circumferential grooves 30 to 33 are all formed by cutting.
　最も底部１３側にある周溝３０は、取付穴２４，２５のうちの底部１３側の取付穴２４の近傍に形成されている。この周溝３０内には、周溝３０に保持されるように、円環状のピストンシール３５が配置されている。 The circumferential groove 30 on the most bottom 13 side is formed in the vicinity of the mounting hole 24 on the bottom 13 side of the mounting holes 24 and 25. An annular piston seal 35 is disposed in the circumferential groove 30 so as to be held in the circumferential groove 30.
　シリンダ本体１５の摺動内径部２８における周溝３０よりも開口部１６側には、底部１３側の取付穴２４から穿設される連通穴３６を筒部１４内に開口させるように、シリンダ径方向外側に凹む環状の開口溝３７が形成されている。ここで、この開口溝３７と連通穴３６とが、シリンダ本体１５に設けられてリザーバ１２に常時連通するセカンダリ補給路（補給路）３８を主に構成している。 The cylinder diameter is such that a communication hole 36 formed from the mounting hole 24 on the bottom portion 13 side is opened in the cylindrical portion 14 on the opening portion 16 side of the sliding inner diameter portion 28 of the cylinder body 15 on the opening portion 16 side. An annular opening groove 37 that is recessed outward in the direction is formed. Here, the opening groove 37 and the communication hole 36 mainly constitute a secondary supply path (supply path) 38 provided in the cylinder body 15 and always communicating with the reservoir 12.
　シリンダ本体１５の摺動内径部２８には、周溝３０内に開口するとともに周溝３０からシリンダ軸方向に直線状に底部１３側に向け延出する図示略の連通溝が、シリンダ径方向外側に凹むように形成されている。この連通溝は、底部１３と周溝３０との間であって底部１３の近傍となる位置に形成されたセカンダリ吐出路２６と周溝３０とを後述のセカンダリ圧力室６８を介して連通させる。 The sliding inner diameter portion 28 of the cylinder body 15 has a communication groove (not shown) that opens into the circumferential groove 30 and extends linearly from the circumferential groove 30 toward the bottom portion 13 in the cylinder axial direction. It is formed so as to be recessed. The communication groove communicates the secondary discharge passage 26 and the circumferential groove 30 formed at a position between the bottom portion 13 and the circumferential groove 30 and in the vicinity of the bottom portion 13 through a secondary pressure chamber 68 described later.
　シリンダ本体１５の摺動内径部２８には、シリンダ軸線方向における上記開口溝３７の周溝３０とは反対側つまり開口部１６側に、上記周溝３１が形成されている。この周溝３１内には、周溝３１に保持されるように、円環状の区画シール４２が配置されている。 The circumferential groove 31 is formed in the sliding inner diameter portion 28 of the cylinder body 15 on the side opposite to the circumferential groove 30 of the opening groove 37 in the cylinder axial direction, that is, on the opening 16 side. An annular partition seal 42 is disposed in the circumferential groove 31 so as to be held in the circumferential groove 31.
　シリンダ本体１５の摺動内径部２９には、開口部１６側の取付穴２５の近傍に、上記した周溝３２が形成されている。この周溝３２内には、周溝３２に保持されるように、円環状のピストンシール４５が配置されている。 The above-described circumferential groove 32 is formed in the sliding inner diameter portion 29 of the cylinder body 15 in the vicinity of the mounting hole 25 on the opening 16 side. An annular piston seal 45 is disposed in the circumferential groove 32 so as to be held in the circumferential groove 32.
　シリンダ本体１５の摺動内径部２９におけるこの周溝３２の開口部１６側には、開口部１６側の取付穴２５から穿設される連通穴４６を筒部１４内に開口させるように、シリンダ径方向外側に凹む環状の開口溝４７が形成されている。ここで、この開口溝４７と連通穴４６とが、シリンダ本体１５に設けられてリザーバ１２に常時連通するプライマリ補給路（補給路）４８を主に構成している。 In the sliding inner diameter portion 29 of the cylinder body 15, on the opening portion 16 side of the circumferential groove 32, a communication hole 46 drilled from the mounting hole 25 on the opening portion 16 side is opened in the cylinder portion 14. An annular opening groove 47 that is recessed outward in the radial direction is formed. Here, the opening groove 47 and the communication hole 46 mainly constitute a primary supply path (supply path) 48 provided in the cylinder body 15 and always communicating with the reservoir 12.
　シリンダ本体１５の摺動内径部２９の周溝３２の底部１３側には、周溝３２に開口するとともに周溝３２からシリンダ軸方向に直線状に底部１３側に向け延出する図示略の連通溝が、シリンダ径方向外側に凹むように形成されている。この連通溝は、周溝３１の近傍となる位置に形成されたプライマリ吐出路２７と周溝３２とを後述するプライマリ圧力室８５を介して連通させる。 On the bottom 13 side of the circumferential groove 32 of the sliding inner diameter portion 29 of the cylinder body 15, an unillustrated communication that opens to the circumferential groove 32 and extends linearly from the circumferential groove 32 toward the bottom 13 side in the cylinder axial direction. The groove is formed to be recessed outward in the cylinder radial direction. The communication groove communicates the primary discharge passage 27 formed at a position near the circumferential groove 31 and the circumferential groove 32 via a primary pressure chamber 85 described later.
　シリンダ本体１５の摺動内径部２９における上記開口溝４７の周溝３２とは反対側、つまり開口部１６側に周溝３３が形成されている。この周溝３３内には、周溝３３に保持されるように、円環状の区画シール５２が配置されている。 A circumferential groove 33 is formed in the sliding inner diameter portion 29 of the cylinder body 15 on the side opposite to the circumferential groove 32 of the opening groove 47, that is, on the opening 16 side. An annular partition seal 52 is disposed in the circumferential groove 33 so as to be held in the circumferential groove 33.
　シリンダ本体１５の底部１３側に嵌合されるセカンダリピストン１９は、円筒状部５５と、円筒状部５５の軸線方向における一側に形成された底部５６とを有する有底円筒状をなしている。上記内周孔２２は、これら円筒状部５５と底部５６とにより形成されている。セカンダリピストン１９は、円筒状部５５をシリンダ本体１５の底部１３側に配置した状態で、シリンダ本体１５の摺動内径部２８に設けられたピストンシール３５および区画シール４２のそれぞれの内周に摺動可能に嵌合される。円筒状部５５の底部５６に対し反対の端側外周部には、セカンダリピストン１９において最も大径の外径部５８よりも径方向内方に位置するように段差状をなす環状の段部５９が形成されている。この段部５９には、その底部５６側にシリンダ径方向に貫通するポート６０が複数、シリンダ周方向の等間隔位置に、放射状となるように形成されている。 The secondary piston 19 fitted to the bottom 13 side of the cylinder body 15 has a bottomed cylindrical shape having a cylindrical portion 55 and a bottom portion 56 formed on one side in the axial direction of the cylindrical portion 55. . The inner peripheral hole 22 is formed by the cylindrical portion 55 and the bottom portion 56. The secondary piston 19 is slid on the inner periphery of each of the piston seal 35 and the partition seal 42 provided on the sliding inner diameter portion 28 of the cylinder body 15 with the cylindrical portion 55 disposed on the bottom 13 side of the cylinder body 15. It is movably fitted. An annular step portion 59 having a step shape so as to be positioned radially inward of the outermost diameter portion 58 of the secondary piston 19 at the outer peripheral portion opposite to the bottom portion 56 of the cylindrical portion 55. Is formed. In the stepped portion 59, a plurality of ports 60 penetrating in the cylinder radial direction are formed on the bottom 56 side so as to be radially formed at equal intervals in the cylinder circumferential direction.
　セカンダリピストン１９とシリンダ本体１５の底部１３との間には、図示せぬブレーキペダル側（図１における右側）から入力がない非制動状態でこれらの間隔を決めるセカンダリピストンスプリング６２を含む間隔調整部６３が設けられている。この間隔調整部６３は、シリンダ本体１５の底部１３に当接する係止部材６４と、この係止部材６４に所定範囲内でのみ摺動するように連結されてセカンダリピストン１９の底部５６に当接する係止部材６５とを有している。上記セカンダリピストンスプリング６２は、両側の係止部材６４，６５間に介装されている。 An interval adjustment unit including a secondary piston spring 62 between the secondary piston 19 and the bottom portion 13 of the cylinder body 15 for determining these intervals in a non-braking state without input from a brake pedal (not shown) (right side in FIG. 1). 63 is provided. The interval adjusting portion 63 is connected to the locking member 64 that contacts the bottom portion 13 of the cylinder body 15 and the locking member 64 so as to slide only within a predetermined range, and contacts the bottom portion 56 of the secondary piston 19. And a locking member 65. The secondary piston spring 62 is interposed between the locking members 64 and 65 on both sides.
　ここで、シリンダ本体１５の底部１３および筒部１４の底部１３側とセカンダリピストン１９とで囲まれて形成される部分が、ブレーキ液圧を発生してセカンダリ吐出路２６にブレーキ液圧を供給するセカンダリ圧力室（圧力室）６８となっている。言い換えれば、セカンダリピストン１９は、シリンダ本体１５との間に、セカンダリ吐出路２６に液圧を供給するセカンダリ圧力室６８を形成している。このセカンダリ圧力室６８は、セカンダリピストン１９がポート６０を開口溝３７に開口させる位置にあるとき、セカンダリ補給路３８つまりリザーバ１２に連通する。 Here, a portion formed by being surrounded by the bottom portion 13 of the cylinder body 15 and the bottom portion 13 side of the cylinder portion 14 and the secondary piston 19 generates a brake fluid pressure and supplies the brake fluid pressure to the secondary discharge passage 26. A secondary pressure chamber (pressure chamber) 68 is formed. In other words, the secondary piston 19 forms a secondary pressure chamber 68 that supplies hydraulic pressure to the secondary discharge passage 26 between the secondary piston 19 and the cylinder body 15. The secondary pressure chamber 68 communicates with the secondary supply path 38, that is, the reservoir 12 when the secondary piston 19 is in a position for opening the port 60 into the opening groove 37.
　シリンダ本体１５の周溝３１に保持される区画シール４２は、合成ゴムからなる一体成形品である。区画シール４２は、その中心線を含む径方向断面の片側形状がＣ字状をなしている。区画シール４２は、内周が、シリンダ軸方向に移動するセカンダリピストン１９の外周に摺接するとともに、外周がシリンダ本体１５の周溝３１に当接してセカンダリピストン１９およびシリンダ本体１５の区画シール４２の位置の隙間を常時密封する。 The partition seal 42 held in the circumferential groove 31 of the cylinder body 15 is an integrally molded product made of synthetic rubber. The partition seal 42 has a C-shaped one-side shape in a radial section including its center line. The partition seal 42 is in sliding contact with the outer periphery of the secondary piston 19 that moves in the cylinder axial direction, and the outer periphery abuts against the circumferential groove 31 of the cylinder body 15 so that the partition seal 42 of the secondary piston 19 and the cylinder body 15 Always seal position gaps.
　シリンダ本体１５の周溝３０に保持されるピストンシール３５は、ＥＰＤＭ等の合成ゴムからなる一体成形品である。ピストンシール３５は、内周が、シリンダ軸方向に移動するセカンダリピストン１９の外周に摺接するとともに、外周がシリンダ本体１５の周溝３０に当接するように構成されている。このピストンシール３５は、セカンダリピストン１９がポート６０をピストンシール３５よりも底部１３側に位置させた状態では、セカンダリ補給路３８とセカンダリ圧力室６８との間を密封可能、つまり、セカンダリ圧力室６８と、セカンダリ補給路３８およびリザーバ１２との連通を遮断可能となっている。この状態で、セカンダリピストン１９が、シリンダ本体１５の摺動内径部２８およびシリンダ本体１５に保持されたピストンシール３５および区画シール４２の内周で摺動して底部１３側に移動することによって、セカンダリ圧力室６８内のブレーキ液を加圧してセカンダリ吐出路２６から車輪側の制動用シリンダに供給する。 The piston seal 35 held in the circumferential groove 30 of the cylinder body 15 is an integrally molded product made of synthetic rubber such as EPDM. The piston seal 35 is configured such that the inner periphery is in sliding contact with the outer periphery of the secondary piston 19 that moves in the cylinder axis direction, and the outer periphery is in contact with the circumferential groove 30 of the cylinder body 15. The piston seal 35 can seal between the secondary supply passage 38 and the secondary pressure chamber 68 in a state where the secondary piston 19 has the port 60 positioned on the bottom 13 side of the piston seal 35, that is, the secondary pressure chamber 68. The communication with the secondary supply path 38 and the reservoir 12 can be blocked. In this state, the secondary piston 19 slides on the inner circumference of the sliding inner diameter portion 28 of the cylinder body 15 and the piston seal 35 and the partition seal 42 held by the cylinder body 15 and moves to the bottom 13 side. The brake fluid in the secondary pressure chamber 68 is pressurized and supplied from the secondary discharge passage 26 to the brake cylinder on the wheel side.
　なお、図示せぬブレーキペダル側から入力がなく、上述のセカンダリピストン１９が図１に示すようにポート６０を開口溝３７に開口させる位置（非制動位置）にあるときに、ピストンシール３５は、上記セカンダリピストン１９の段部５９内でポート６０にその一部が重なる。そして、セカンダリピストン１９がシリンダ本体１５の底部１３側へ移動してピストンシール３５の内周部がポート６０に全て重なると、セカンダリ圧力室６８とリザーバ１２との連通が遮断される。 When there is no input from the brake pedal (not shown) and the secondary piston 19 is in a position (non-braking position) where the port 60 is opened in the opening groove 37 as shown in FIG. A portion of the secondary piston 19 overlaps the port 60 in the stepped portion 59 of the secondary piston 19. When the secondary piston 19 moves to the bottom 13 side of the cylinder body 15 and the inner peripheral portion of the piston seal 35 is completely overlapped with the port 60, the communication between the secondary pressure chamber 68 and the reservoir 12 is blocked.
　シリンダ本体１５の開口部１６側に嵌合されるプライマリピストン１８は、第１円筒状部７１と、第１円筒状部７１の軸線方向における一側に形成された底部７２と、底部７２の第１円筒状部７１とは反対側に形成された第２円筒状部７３とを有する形状をなしている。上記内周孔２１は、これらのうちの第１円筒状部７１と底部７２とにより形成されている。プライマリピストン１８は、第１円筒状部７１をシリンダ本体１５内のセカンダリピストン１９側に配置した状態で、シリンダ本体１５の摺動内径部２９に設けられたピストンシール４５および区画シール５２のそれぞれの内周に摺動可能に嵌合されている。ここで、第２円筒状部７３の内側には、ブレーキブースタの出力軸が挿入され、この出力軸によって底部７２が押圧される。 The primary piston 18 fitted to the opening 16 side of the cylinder body 15 includes a first cylindrical portion 71, a bottom portion 72 formed on one side in the axial direction of the first cylindrical portion 71, and a first portion of the bottom portion 72. It has a shape having a second cylindrical portion 73 formed on the opposite side to the first cylindrical portion 71. The inner peripheral hole 21 is formed by the first cylindrical portion 71 and the bottom portion 72 among them. The primary piston 18 has the first cylindrical portion 71 disposed on the secondary piston 19 side in the cylinder body 15 and each of the piston seal 45 and the partition seal 52 provided on the sliding inner diameter portion 29 of the cylinder body 15. The inner periphery is slidably fitted. Here, the output shaft of the brake booster is inserted inside the second cylindrical portion 73, and the bottom portion 72 is pressed by this output shaft.
　第１円筒状部７１の底部７２に対し反対の端側外周部には、プライマリピストン１８において最も大径の外径部７４よりも径方向内方に位置するように段差状をなす環状の段部７５が形成されている。この段部７５には、その底部７２側に径方向に貫通するポート７６が複数、シリンダ周方向の等間隔位置に、放射状となるように形成されている。 An annular step having a step shape so as to be positioned radially inward of the outermost diameter portion 74 of the primary piston 18 at the outer peripheral portion on the end opposite to the bottom portion 72 of the first cylindrical portion 71. A portion 75 is formed. The step portion 75 is formed with a plurality of ports 76 penetrating in the radial direction on the bottom portion 72 side so as to be radially arranged at equal intervals in the cylinder circumferential direction.
　セカンダリピストン１９とプライマリピストン１８との間には、図示せぬブレーキペダル側（図１における右側）から入力がない非制動状態でこれらの間隔を決めるプライマリピストンスプリング７８を含む間隔調整部７９が設けられている。この間隔調整部７９は、プライマリピストン１８の底部７２に当接する係止部材８１と、セカンダリピストン１９の底部５６に当接する係止部材８２と、係止部材８１に一端部が固定されるとともに係止部材８２を所定範囲内でのみ摺動自在に支持する軸部材８３とを有している。上記プライマリピストンスプリング７８は、両側の係止部材８１，８２間に介装されている。 Between the secondary piston 19 and the primary piston 18, there is provided a distance adjusting portion 79 including a primary piston spring 78 that determines these distances in a non-braking state without input from a brake pedal side (right side in FIG. 1). It has been. The gap adjusting portion 79 includes a locking member 81 that contacts the bottom 72 of the primary piston 18, a locking member 82 that contacts the bottom 56 of the secondary piston 19, and one end fixed to the locking member 81. And a shaft member 83 that slidably supports the stop member 82 only within a predetermined range. The primary piston spring 78 is interposed between the locking members 81 and 82 on both sides.
　ここで、シリンダ本体１５の筒部１４とプライマリピストン１８とセカンダリピストン１９とで囲まれて形成される部分が、ブレーキ液圧を発生してプライマリ吐出路２７にブレーキ液を供給するプライマリ圧力室（圧力室）８５となっている。言い換えれば、プライマリピストン１８は、セカンダリピストン１９とシリンダ本体１５との間に、プライマリ吐出路２７に液圧を供給するプライマリ圧力室８５を形成している。このプライマリ圧力室８５は、プライマリピストン１８がポート７６を開口溝４７に開口させる位置にあるとき、プライマリ補給路４８つまりリザーバ１２に連通するように構成されている。 Here, a portion surrounded by the cylinder portion 14 of the cylinder body 15, the primary piston 18 and the secondary piston 19 generates a brake fluid pressure and supplies a brake fluid to the primary discharge passage 27 (primary pressure chamber ( Pressure chamber) 85. In other words, the primary piston 18 forms a primary pressure chamber 85 that supplies hydraulic pressure to the primary discharge passage 27 between the secondary piston 19 and the cylinder body 15. The primary pressure chamber 85 is configured to communicate with the primary supply path 48, that is, the reservoir 12 when the primary piston 18 is in a position where the port 76 is opened to the opening groove 47.
　シリンダ本体１５の周溝３３に保持される区画シール５２は、区画シール４２と同じ部品であり、合成ゴムからなる一体成形品である。区画シール５２は、その中心線を含む径方向断面の片側形状がＣ字状をなしている。区画シール５２は、内周が、シリンダ軸方向に移動するプライマリピストン１８の外周に摺接するとともに、外周がシリンダ本体１５の周溝３３に当接してプライマリピストン１８およびシリンダ本体１５の区画シール５２の位置の隙間を常時密封する。 The partition seal 52 held in the circumferential groove 33 of the cylinder body 15 is the same component as the partition seal 42 and is an integrally molded product made of synthetic rubber. The partition seal 52 has a C-shaped one-side shape in a radial cross section including its center line. The partition seal 52 is in sliding contact with the outer periphery of the primary piston 18 that moves in the cylinder axis direction, and the outer periphery abuts on the circumferential groove 33 of the cylinder body 15 so that the partition seal 52 of the primary piston 18 and the cylinder body 15 Always seal position gaps.
　シリンダ本体１５の周溝３２に保持されるピストンシール４５は、ピストンシール３５と同じ部品であり、合成ゴムからなる一体成形品である。ピストンシール４５は、内周が、シリンダ軸方向に移動するプライマリピストン１８の外周に摺接するとともに、外周がシリンダ本体１５の周溝３２に当接するように構成されている。このピストンシール４５は、プライマリピストン１８がポート７６をピストンシール４５よりも底部１３側に位置させた状態では、プライマリ補給路４８とプライマリ圧力室８５との間を密封可能、つまり、プライマリ圧力室８５と、プライマリ補給路４８およびリザーバ１２との連通を遮断可能である。この状態で、プライマリピストン１８が、シリンダ本体１５の摺動内径部２９およびシリンダ本体１５に保持されたピストンシール４５および区画シール５２の内周で摺動して底部１３側に移動することによって、プライマリ圧力室８５内のブレーキ液を加圧してプライマリ吐出路２７から車輪側の制動用シリンダに供給する。 The piston seal 45 held in the circumferential groove 32 of the cylinder body 15 is the same component as the piston seal 35 and is an integrally molded product made of synthetic rubber. The piston seal 45 is configured such that the inner circumference is in sliding contact with the outer circumference of the primary piston 18 moving in the cylinder axial direction, and the outer circumference is in contact with the circumferential groove 32 of the cylinder body 15. The piston seal 45 can seal between the primary supply passage 48 and the primary pressure chamber 85 when the primary piston 18 has the port 76 positioned on the bottom 13 side of the piston seal 45, that is, the primary pressure chamber 85. The communication with the primary supply path 48 and the reservoir 12 can be blocked. In this state, the primary piston 18 slides on the sliding inner diameter portion 29 of the cylinder body 15 and the inner periphery of the piston seal 45 and the partition seal 52 held by the cylinder body 15 and moves to the bottom 13 side. The brake fluid in the primary pressure chamber 85 is pressurized and supplied from the primary discharge path 27 to the brake cylinder on the wheel side.
　なお、図示せぬブレーキペダル側から入力がなく、上述のプライマリピストン１８が図１に示すようにポート７６を開口溝４７に開口させる位置（非制動位置）にあるときに、ピストンシール４５は、上記プライマリピストン１８の段部７５内でポート７６にその一部が重なる。そして、プライマリピストン１８がシリンダ本体１５の底部１３側へ移動してピストンシール４５の内周部がポート７６に全て重なると、プライマリ圧力室８５とリザーバ１２との連通が遮断される。 When there is no input from the brake pedal (not shown) and the above-described primary piston 18 is in a position (non-braking position) where the port 76 is opened in the opening groove 47 as shown in FIG. Part of the port 76 overlaps the port 76 in the step 75 of the primary piston 18. When the primary piston 18 moves to the bottom 13 side of the cylinder body 15 and the inner peripheral portion of the piston seal 45 is completely overlapped with the port 76, the communication between the primary pressure chamber 85 and the reservoir 12 is blocked.
　シリンダ本体１５の周溝３０およびその近傍部分と、ピストンシール３５と、セカンダリピストン１９のピストンシール３５の摺接部分とからなるセカンダリ側のシール構造部ＳＳと、シリンダ本体１５の周溝３２およびその近傍部分と、ピストンシール４５と、プライマリピストン１８のピストンシール４５の摺接部分とからなるプライマリ側のシール構造部ＳＰとは、同様の構造となっている。したがって、以下においては、これらの詳細についてプライマリ側のシール構造部ＳＰを例にとり、主に図２～図７を参照して説明する。 The secondary side seal structure SS composed of the circumferential groove 30 of the cylinder body 15 and the vicinity thereof, the piston seal 35 and the sliding contact portion of the piston seal 35 of the secondary piston 19, the circumferential groove 32 of the cylinder body 15 and The primary side seal structure SP composed of the vicinity portion, the piston seal 45, and the sliding contact portion of the piston seal 45 of the primary piston 18 has the same structure. Therefore, in the following, these details will be described with reference to FIGS. 2 to 7 mainly by taking the seal structure SP on the primary side as an example.
　図２に示すように、周溝３２は、シリンダ径方向の最も外側（図２における上側）にあってシリンダ軸を中心とする円筒面状をなす溝底部（周溝３２の底部）８８と、溝底部８８におけるシリンダ本体１５の開口部１６側（図２における右側）の端縁部からシリンダ軸の直交方向に沿ってシリンダ径方向内方に延出する周壁８９と、溝底部８８におけるシリンダ本体１５の底部１３側（図２における左側）の端縁部からシリンダ軸の直交方向に沿ってシリンダ径方向内方に延出する周壁９０と、を有している。これら溝底部８８、周壁８９および周壁９０は、シリンダ本体１５に一体的に形成されており、シリンダ本体１５に対する切削加工により形成されている。 As shown in FIG. 2, the circumferential groove 32 is a groove bottom portion (bottom portion of the circumferential groove 32) 88 that is on the outermost side in the cylinder radial direction (upper side in FIG. 2) and has a cylindrical surface shape around the cylinder axis. A peripheral wall 89 extending inwardly in the cylinder radial direction along the direction orthogonal to the cylinder axis from the edge of the opening 15 side (right side in FIG. 2) of the cylinder body 15 at the groove bottom 88, and the cylinder body at the groove bottom 88 15 has a peripheral wall 90 extending inwardly in the cylinder radial direction along the direction orthogonal to the cylinder axis from the edge of the bottom 13 side (left side in FIG. 2). The groove bottom portion 88, the peripheral wall 89, and the peripheral wall 90 are formed integrally with the cylinder body 15 and are formed by cutting the cylinder body 15.
　周壁８９は、シリンダ軸の直交面に平行な平坦面からなる平坦面部８９ａと、平坦面部８９ａよりもシリンダ径方向の内側に設けられるＲ面取り部８９ｂとを有している。平坦面部８９ａは、一定内径かつ一定外径でシリンダ径方向に一定幅となっており、シリンダ軸を中心とする円環状をなしている。 The peripheral wall 89 has a flat surface portion 89a composed of a flat surface parallel to a plane orthogonal to the cylinder axis, and an R chamfered portion 89b provided on the inner side in the cylinder radial direction than the flat surface portion 89a. The flat surface portion 89a has a constant inner diameter and a constant outer diameter, a constant width in the cylinder radial direction, and has an annular shape centering on the cylinder axis.
　Ｒ面取り部８９ｂは、平坦面部８９ａのシリンダ径方向の内端縁部からシリンダ径方向の内側ほどシリンダ本体１５の開口部１６側（図２における右側）に位置するようにシリンダ軸方向に対し傾いて延出している。Ｒ面取り部８９ｂは、シリンダ軸を含む断面の形状が周溝３２の外側に中心を有する円弧状をなしている。Ｒ面取り部８９ｂは、シリンダ軸を中心とする円環状をなしており、シリンダ径方向の内端縁部が、摺動内径部２９の周溝３２よりも開口部１６側（図２における右側）の部分に繋がっている。 The R chamfered portion 89b is inclined with respect to the cylinder axial direction so as to be located closer to the opening 16 side (right side in FIG. 2) of the cylinder body 15 from the inner end edge in the cylinder radial direction of the flat surface portion 89a to the inner side in the cylinder radial direction. Is extended. The R chamfered portion 89b has an arc shape in which the cross-sectional shape including the cylinder shaft has a center outside the circumferential groove 32. The R chamfered portion 89b has an annular shape centering on the cylinder axis, and the inner end edge in the cylinder radial direction is closer to the opening 16 than the circumferential groove 32 of the sliding inner diameter portion 29 (right side in FIG. 2). It is connected to the part.
　周壁８９に対向する周壁９０は、シリンダ軸の直交面に平行な平坦面からなる平坦面部（壁面部）９０ａと、平坦面部９０ａよりもシリンダ径方向の内側に設けられるテーパ面部９０ｂと、テーパ面部９０ｂよりもシリンダ径方向の内側に設けられるＲ面取り部９０ｃとを有している。平坦面部９０ａは、一定内径かつ一定外径でシリンダ径方向に一定幅となっており、シリンダ軸を中心とする円環状をなしている。 The peripheral wall 90 facing the peripheral wall 89 includes a flat surface portion (wall surface portion) 90a formed of a flat surface parallel to the orthogonal surface of the cylinder axis, a tapered surface portion 90b provided on the inner side in the cylinder radial direction than the flat surface portion 90a, and a tapered surface portion. R chamfered portion 90c provided on the inner side in the cylinder radial direction than 90b. The flat surface portion 90a has a constant inner diameter and a constant outer diameter, a constant width in the cylinder radial direction, and has an annular shape centering on the cylinder axis.
　テーパ面部９０ｂは、平坦面部９０ａのシリンダ径方向の内端縁部からシリンダ軸方向の底部１３側（図２における左側）に、底部１３側ほど縮径するようにシリンダ軸を中心とするテーパ状をなして延出している。このテーパ面部９０ｂは、周溝３２のシリンダ本体１５の底部１３側（図２における左側）の周壁９０における周溝３２の開口側（径方向内側）に形成されている。このテーパ面部９０ｂのシリンダ径方向の溝底部８８側には平坦面部９０ａが隣り合って形成されている。テーパ面部９０ｂの最大径は、周壁８９の平坦面部８９ａの最小径よりも大径となっている。テーパ面部９０ｂは、平坦面部９０ａとのなす角度が鈍角となっている。 The tapered surface portion 90b has a tapered shape centered on the cylinder shaft so that the diameter is reduced toward the bottom 13 side (left side in FIG. 2) in the cylinder axial direction from the inner end edge portion of the flat surface portion 90a in the cylinder radial direction. Is extended. The tapered surface portion 90b is formed on the opening side (in the radial direction) of the circumferential groove 32 in the circumferential wall 90 on the bottom 13 side (left side in FIG. 2) of the cylinder body 15 of the circumferential groove 32. A flat surface 90a is formed adjacent to the taper surface 90b on the side of the groove bottom 88 in the cylinder radial direction. The maximum diameter of the tapered surface portion 90 b is larger than the minimum diameter of the flat surface portion 89 a of the peripheral wall 89. The tapered surface portion 90b has an obtuse angle with the flat surface portion 90a.
　Ｒ面取り部９０ｃは、テーパ面部９０ｂのシリンダ径方向の内端縁部から、シリンダ径方向の内側ほどシリンダ本体１５の底部１３側（図２における左側）に位置するようにシリンダ軸方向に対し傾いて延出している。Ｒ面取り部９０ｃは、シリンダ軸を含む断面の形状が周溝３２の外側に中心を有する円弧状をなしている。Ｒ面取り部９０ｃは、全体としてシリンダ軸を中心とする円環状をなしており、そのシリンダ径方向の内端縁部が、摺動内径部２９の周溝３２よりも底部１３側（図２における左側）の部分に繋がっている。 The R chamfered portion 90c is inclined with respect to the cylinder axial direction so as to be located on the bottom 13 side (the left side in FIG. 2) of the cylinder body 15 from the inner end edge in the cylinder radial direction of the tapered surface 90b to the inner side in the cylinder radial direction. Is extended. The R chamfered portion 90 c has an arc shape in which the cross-sectional shape including the cylinder axis has a center outside the circumferential groove 32. The R chamfered portion 90c has an annular shape centering on the cylinder shaft as a whole, and the inner end edge portion in the cylinder radial direction is on the bottom 13 side of the circumferential groove 32 of the sliding inner diameter portion 29 (in FIG. 2). (Left side)
　プライマリピストン１８に形成された段部７５は、プライマリピストン１８において最も大径の円筒面状の外径部７４よりも小径の一定径に形成される円筒面部７５ａと、この円筒面部７５ａのシリンダ本体１５の開口部１６側（図２における右側）の端縁部からシリンダ本体１５の開口部１６側ほど大径となるように傾斜して延出するテーパ面部７５ｂと、円筒面部７５ａのシリンダ本体１５の底部１３側（図２における左側）の端縁部からシリンダ本体１５の底部１３側ほど大径となるように傾斜して延出するテーパ面部７５ｃとからなっている。 The stepped portion 75 formed in the primary piston 18 includes a cylindrical surface portion 75a formed with a constant diameter smaller than the outermost diameter portion 74 having the largest diameter in the primary piston 18, and a cylinder body of the cylindrical surface portion 75a. A tapered surface portion 75b extending so as to increase in diameter toward the opening portion 16 side of the cylinder body 15 from an end edge portion on the opening portion 16 side (right side in FIG. 2) of the cylinder 15 and a cylinder body 15 of the cylindrical surface portion 75a. And a taper surface portion 75c extending so as to increase in diameter from the edge on the bottom 13 side (left side in FIG. 2) toward the bottom 13 side of the cylinder body 15.
　これら円筒面部７５ａ、テーパ面部７５ｂおよびテーパ面部７５ｃは、外径部７４と同様にプライマリピストン１８の中心軸を中心に形成されている。テーパ面部７５ｂの大径側およびテーパ面部７５ｃの大径側がそれぞれ外径部７４に繋がっている。プライマリ圧力室８５に常時連通するポート７６は、円筒面部７５ａおよびテーパ面部７５ｂの両方に架かる位置に形成されている。言い換えれば、ポート７６のシリンダ本体１５の底部１３側（図２における左側）の端部が円筒面部７５ａに位置している。ポート７６のシリンダ本体１５の開口部１６側の端部がテーパ面部７５ｂに位置している。 The cylindrical surface portion 75 a, the tapered surface portion 75 b and the tapered surface portion 75 c are formed around the central axis of the primary piston 18 like the outer diameter portion 74. The large diameter side of the tapered surface portion 75b and the large diameter side of the tapered surface portion 75c are connected to the outer diameter portion 74, respectively. The port 76 that always communicates with the primary pressure chamber 85 is formed at a position that spans both the cylindrical surface portion 75a and the tapered surface portion 75b. In other words, the end of the port 76 on the bottom 13 side (the left side in FIG. 2) of the cylinder body 15 is positioned on the cylindrical surface portion 75a. The end of the port 76 on the side of the opening 16 of the cylinder body 15 is located on the tapered surface portion 75b.
　周溝３２に配置されるピストンシール４５は、ＥＰＤＭ等の合成ゴムからなる一体成形品である。ピストンシール４５は、シリンダ本体１５の開口部１６側（図２における右側）に配置される円環板状の基部１０１と、基部１０１の内周端から基部１０１の軸線方向に沿ってシリンダ本体１５の底部１３側（図２における左側）に向けて突出する円環筒状の内周リップ部１０２と、基部１０１の外周端からシリンダ本体１５の底部１３側（図２における左側）に向けて突出する円環筒状の外周リップ部１０３と、外周リップ部１０３と内周リップ部１０２との間で基部１０１からシリンダ本体１５の底部１３側（図２における左側）に向けて外周リップ部１０３よりも先まで突出する円環筒状の中間突出部１０４とを有している。図３Ａに示すように、これら基部１０１、内周リップ部１０２、外周リップ部１０３および中間突出部１０４は、中心軸を一致させている。この中心軸がピストンシール４５の中心軸となっている。ピストンシール４５は、図２に示すように、内周リップ部１０２が、シリンダ軸方向に移動するプライマリピストン１８の外周面１８ａに摺接する。外周リップ部１０３が、シリンダ本体１５の周溝３２に当接する。 The piston seal 45 disposed in the circumferential groove 32 is an integrally molded product made of synthetic rubber such as EPDM. The piston seal 45 includes an annular plate-like base 101 disposed on the opening 16 side (right side in FIG. 2) of the cylinder main body 15, and the cylinder main body 15 along the axial direction of the base 101 from the inner peripheral end of the base 101. An annular cylindrical inner peripheral lip portion 102 projecting toward the bottom 13 side (left side in FIG. 2), and projecting from the outer peripheral end of the base 101 toward the bottom 13 side (left side in FIG. 2) of the cylinder body 15 The outer peripheral lip 103 formed between the outer peripheral lip 103 and the outer peripheral lip 103 and the inner peripheral lip 102 from the base 101 toward the bottom 13 of the cylinder body 15 (left side in FIG. 2). And an annular cylindrical intermediate projecting portion 104 projecting to the tip. As shown in FIG. 3A, the base portion 101, the inner peripheral lip portion 102, the outer peripheral lip portion 103, and the intermediate protruding portion 104 have the same center axis. This central axis is the central axis of the piston seal 45. As shown in FIG. 2, in the piston seal 45, the inner peripheral lip portion 102 is in sliding contact with the outer peripheral surface 18a of the primary piston 18 moving in the cylinder axial direction. The outer peripheral lip 103 contacts the peripheral groove 32 of the cylinder body 15.
　図３Ａ、図３Ｂ、図４Ａ及び図４Ｂを参照して、マスタシリンダ１１に組み込まれる前の自然状態にあるピストンシール４５について説明する。 3A, 3B, 4A, and 4B, the piston seal 45 in a natural state before being incorporated into the master cylinder 11 will be described.
　図４Ａに示すように、基部１０１は、内周リップ部１０２、外周リップ部１０３および中間突出部１０４の突出方向とは反対側の端面である背面部１０１ａが、ピストンシール４５の軸直交面に平行をなしている。この背面部１０１ａは、一定内径かつ一定外径で径方向に一定幅となっており、ピストンシール４５の中心軸を中心とする円環状をなしている。 As shown in FIG. 4A, the base 101 has a back surface 101 a, which is the end surface opposite to the protruding direction of the inner peripheral lip 102, the outer peripheral lip 103, and the intermediate protruding portion 104, on the axis orthogonal surface of the piston seal 45. They are parallel. The back surface portion 101 a has a constant inner diameter and a constant outer diameter, a constant width in the radial direction, and has an annular shape centering on the central axis of the piston seal 45.
　また、基部１０１は、背面部１０１ａの径方向内側にＲ面取り部１０１ｂが形成されている。背面部１０１ａの径方向外側にＲ面取り部１０１ｃが形成されている。Ｒ面取り部１０１ｂは、背面部１０１ａの径方向の内端縁部から、背面部１０１ａから径方向内方に離れるほど軸方向の内周リップ部１０２側に位置するようにピストンシール４５の中心軸に対して傾斜して延出している。Ｒ面取り部１０１ｂは、ピストンシール４５の中心軸を含む断面の形状が基部１０１の内部側に中心を有する円弧状をなしている。Ｒ面取り部１０１ｂは、全体としてピストンシール４５の中心軸を中心とする円環状をなしている。Ｒ面取り部１０１ｃは、背面部１０１ａの径方向の外端縁部から、背面部１０１ａから径方向外方に離れるほど軸方向の外周リップ部１０３側に位置するようにピストンシール４５の中心軸に対して傾斜して延出している。Ｒ面取り部１０１ｃは、ピストンシール４５の中心軸を含む断面の形状が基部１０１の内部側に中心を有する円弧状をなしている。Ｒ面取り部１０１ｃは、全体としてピストンシール４５の中心軸を中心とする円環状をなしている。 Also, the base 101 has an R chamfered portion 101b formed on the inner side in the radial direction of the back surface portion 101a. An R chamfered portion 101c is formed on the radially outer side of the back surface portion 101a. The central axis of the piston seal 45 is such that the R chamfered portion 101b is positioned closer to the inner peripheral lip portion 102 in the axial direction as it is farther inward in the radial direction from the rear surface portion 101a from the radially inner end edge portion of the rear surface portion 101a. Inclined and extended. The R chamfered portion 101 b has an arc shape in which a cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the base portion 101. The R chamfered portion 101b has an annular shape centering on the central axis of the piston seal 45 as a whole. The R chamfered portion 101c is formed on the central axis of the piston seal 45 so as to be positioned on the outer peripheral lip portion 103 side in the axial direction as the distance from the outer end edge portion in the radial direction of the back surface portion 101a increases radially outward from the back surface portion 101a. It is inclined and extended. The R chamfered portion 101 c has an arc shape in which a cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the base portion 101. The R chamfered portion 101 c has an annular shape centering on the central axis of the piston seal 45 as a whole.
　内周リップ部１０２は、基部１０１から軸方向に離れるほど全体として若干小径となるテーパ筒状をなしている。内周リップ部１０２の内周側には、軸方向の基部１０１側から順に、縮径内周面部１０２ａと、拡径内周面部１０２ｂと、円筒内周面部１０２ｃとが形成されている。縮径内周面部１０２ａは、基部１０１のＲ面取り部１０１ｂのピストンシール４５の径方向における内端縁部から、基部１０１から軸方向に離れるほど小径となる（つまり縮径する）ように、ピストンシール４５の中心軸を中心とするテーパ状をなして延出している。拡径内周面部１０２ｂは、縮径内周面部１０２ａの基部１０１とは反対側の端縁部から、基部１０１から軸方向に離れるほど大径となる（つまり拡径する）ように、ピストンシール４５の中心軸を中心とするテーパ状をなして延出している。円筒内周面部１０２ｃは、拡径内周面部１０２ｂの基部１０１とは反対側の端縁部から、ピストンシール４５の中心軸を中心とする円筒面状をなして延出している。 The inner peripheral lip portion 102 has a tapered cylindrical shape with a small diameter as a whole as it moves away from the base portion 101 in the axial direction. On the inner peripheral side of the inner peripheral lip portion 102, a reduced diameter inner peripheral surface portion 102a, an enlarged diameter inner peripheral surface portion 102b, and a cylindrical inner peripheral surface portion 102c are formed in this order from the base 101 side in the axial direction. The diameter-reduced inner peripheral surface portion 102a is a piston whose diameter decreases from the inner end edge portion of the R chamfered portion 101b of the base portion 101 in the radial direction of the piston seal 45 in the axial direction. The seal 45 extends in a tapered shape with the central axis as the center. The piston seal is formed so that the enlarged inner peripheral surface portion 102b has a larger diameter (that is, the diameter is increased) from the end edge portion of the reduced inner peripheral surface portion 102a opposite to the base portion 101 in the axial direction. It extends in a tapered shape with the central axis of 45 as the center. The cylindrical inner peripheral surface portion 102 c extends in a cylindrical surface shape centering on the central axis of the piston seal 45 from the end edge portion of the enlarged diameter inner peripheral surface portion 102 b opposite to the base portion 101.
　内周リップ部１０２の外周側には、軸方向の基部１０１側から順に、縮径外周面部１０２ｄと、Ｒ面取り部１０２ｅとが形成されている。縮径外周面部１０２ｄは、基部１０１から、軸方向に離れるほど若干小径となるようにピストンシール４５の中心軸を中心とするテーパ状をなして延出している。Ｒ面取り部１０２ｅは、縮径外周面部１０２ｄの基部１０１とは反対側の端縁部から、基部１０１から軸方向に離れるほど小径となるように、ピストンシール４５の中心軸に対し傾斜して延出している。Ｒ面取り部１０２ｅは、ピストンシール４５の中心軸を含む断面の形状が内周リップ部１０２の内部側に中心を有する円弧状をなしている。Ｒ面取り部１０２ｅは、全体としてピストンシール４５の中心軸を中心とする円環状をなしている。 On the outer peripheral side of the inner peripheral lip portion 102, a reduced-diameter outer peripheral surface portion 102d and an R chamfered portion 102e are formed in this order from the base 101 side in the axial direction. The reduced-diameter outer peripheral surface portion 102d extends from the base portion 101 in a taper shape centering on the central axis of the piston seal 45 so as to be slightly smaller in diameter in the axial direction. The R chamfered portion 102e extends from the end edge portion of the reduced diameter outer peripheral surface portion 102d opposite to the base portion 101 in an inclined manner with respect to the central axis of the piston seal 45 so that the diameter decreases as the distance from the base portion 101 increases in the axial direction. I'm out. The R chamfered portion 102 e has an arc shape in which the cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the inner peripheral lip portion 102. The R chamfered portion 102e has an annular shape centering on the central axis of the piston seal 45 as a whole.
　円筒内周面部１０２ｃおよびＲ面取り部１０２ｅのそれぞれの基部１０１とは反対側の端縁部が、内周リップ部１０２の基部１０１とは反対側の先端面部１０２ｆに繋がっている。先端面部１０２ｆは、ピストンシール４５の軸直交面に平行をなしており、一定内径かつ一定外径でピストンシール４５の径方向に一定幅となっている。先端面部１０２ｆは、ピストンシール４５の中心軸を中心とする円環状をなしている。 The edge portions of the cylindrical inner peripheral surface portion 102c and the R chamfered portion 102e opposite to the base portion 101 are connected to the distal end surface portion 102f of the inner peripheral lip portion 102 opposite to the base portion 101f. The front end surface portion 102f is parallel to the axis orthogonal surface of the piston seal 45, and has a constant inner diameter and a constant outer diameter, and a constant width in the radial direction of the piston seal 45. The front end surface portion 102 f has an annular shape centering on the central axis of the piston seal 45.
　ここで、内周リップ部１０２は、縮径内周面部１０２ａと拡径内周面部１０２ｂとの境界部分が、内径が最も小径の最小径部１０６となっている。内周リップ部１０２は、基部１０１と最小径部１０６との間の部分が、基部１０１から軸方向に離れるほど厚肉となる先厚部１０７となっており、軸方向の最小径部１０６の位置が最も肉厚が厚くなっている。また、内周リップ部１０２は、軸方向の拡径内周面部１０２ｂの部分が、基部１０１から離れるほど薄肉となる先薄部１０８となっており、軸方向の円筒内周面部１０２ｃの部分が、Ｒ面取り部１０２ｅを除いて一定肉厚となる先端部１０９となっている。 Here, in the inner peripheral lip portion 102, the boundary portion between the reduced inner peripheral surface portion 102a and the expanded inner peripheral surface portion 102b is the smallest diameter portion 106 having the smallest inner diameter. In the inner peripheral lip portion 102, a portion between the base portion 101 and the minimum diameter portion 106 is a tip thick portion 107 that becomes thicker as it moves away from the base portion 101 in the axial direction. The position is the thickest. In addition, the inner peripheral lip portion 102 is a tapered portion 108 in which the portion of the axially enlarged inner peripheral surface portion 102b becomes thinner as it is separated from the base portion 101, and the portion of the cylindrical inner peripheral surface portion 102c in the axial direction is The tip portion 109 has a constant thickness except for the R chamfered portion 102e.
　外周リップ部１０３は、基部１０１から軸方向に離れるほど全体として大径となるようにテーパ筒状をなしている。外周リップ部１０３の内周側には、軸方向の基部１０１側から順に、拡径内周面部１０３ａと、円筒内周面部１０３ｂとが形成されている。拡径内周面部１０３ａは、基部１０１から、軸方向に離れるほど大径となる（つまり拡径する）ようにピストンシール４５の中心軸を中心とするテーパ状をなして延出している。円筒内周面部１０３ｂは、拡径内周面部１０３ａの基部１０１とは反対側の端縁部から、ピストンシール４５の中心軸を中心とする円筒面状をなして延出している。 The outer peripheral lip 103 has a tapered cylindrical shape so that the outer diameter of the outer peripheral lip 103 becomes larger as a distance from the base 101 in the axial direction. On the inner peripheral side of the outer peripheral lip 103, an enlarged inner peripheral surface portion 103a and a cylindrical inner peripheral surface portion 103b are formed in this order from the base 101 side in the axial direction. The diameter-enlarged inner peripheral surface portion 103a extends from the base portion 101 in a taper shape centering on the central axis of the piston seal 45 so as to increase in diameter (that is, increase in diameter) as it moves away in the axial direction. The cylindrical inner peripheral surface portion 103b extends in a cylindrical surface shape around the central axis of the piston seal 45 from an end edge portion of the enlarged diameter inner peripheral surface portion 103a opposite to the base portion 101.
　外周リップ部１０３の外周側には、軸方向の基部１０１側から順に、拡径外周面部１０３ｃと、円筒外周面部１０３ｄと、段面部１０３ｅと、円筒外周面部１０３ｆとが形成されている。拡径外周面部１０３ｃは、基部１０１から、軸方向に離れるほど大径となるようにピストンシール４５の中心軸を中心とするテーパ状をなして延出している。円筒外周面部１０３ｄは、拡径外周面部１０３ｃの基部１０１とは反対側の端縁部から、ピストンシール４５の中心軸を中心とする円筒面状をなして延出している。段面部１０３ｅは、円筒外周面部１０３ｄの基部１０１とは反対側の端縁部から、ピストンシール４５の軸直交面に平行をなして径方向内方に延出している。円筒外周面部１０３ｆは、段面部１０３ｅの内周縁部から、ピストンシール４５の中心軸を中心とする円筒面状をなして延出している。円筒内周面部１０３ｂおよび円筒外周面部１０３ｆのそれぞれの基部１０１とは反対側の端縁部が、外周リップ部１０３の基部１０１とは反対側の先端面部１０３ｇに繋がっている。先端面部１０３ｇは、ピストンシール４５の軸直交面に平行をなしており、一定内径かつ一定外径でピストンシール４５の径方向に一定幅となっていて、ピストンシール４５の中心軸を中心とする円環状をなしている。 On the outer peripheral side of the outer peripheral lip 103, an enlarged outer peripheral surface portion 103c, a cylindrical outer peripheral surface portion 103d, a stepped surface portion 103e, and a cylindrical outer peripheral surface portion 103f are formed in this order from the base 101 side in the axial direction. The diameter-enlarged outer peripheral surface portion 103c extends from the base portion 101 in a tapered shape with the central axis of the piston seal 45 as a center so that the diameter increases as the distance from the base portion 101 increases in the axial direction. The cylindrical outer peripheral surface portion 103 d extends in a cylindrical surface shape centering on the central axis of the piston seal 45 from the end edge portion of the enlarged diameter outer peripheral surface portion 103 c on the side opposite to the base portion 101. The stepped surface portion 103e extends radially inward from the end edge portion of the cylindrical outer peripheral surface portion 103d opposite to the base portion 101 in parallel with the axial orthogonal surface of the piston seal 45. The cylindrical outer peripheral surface portion 103f extends from the inner peripheral edge portion of the step surface portion 103e in a cylindrical surface shape with the central axis of the piston seal 45 as the center. The end portions of the cylindrical inner peripheral surface portion 103 b and the cylindrical outer peripheral surface portion 103 f opposite to the base portion 101 are connected to the distal end surface portion 103 g of the outer peripheral lip portion 103 opposite to the base portion 101 g. The distal end surface portion 103g is parallel to the axial orthogonal surface of the piston seal 45, has a constant inner diameter and a constant outer diameter, has a constant width in the radial direction of the piston seal 45, and is centered on the central axis of the piston seal 45. It has an annular shape.
　ここで、外周リップ部１０３は、円筒外周面部１０３ｆの部分が外周リップ部１０３において他の本体部１１１よりも径方向の肉厚が薄い薄肉部１１２となっている。 Here, the outer peripheral lip portion 103 is a thin-walled portion 112 where the cylindrical outer peripheral surface portion 103f is thinner in the outer peripheral lip portion 103 than the other main body portion 111 in the radial direction.
　中間突出部１０４の内周側には、軸方向の基部１０１側から順に、拡径内周面部１０４ａと、Ｒ面取り部１０４ｂとが形成されている。拡径内周面部１０４ａは、基部１０１から、軸方向に離れるほど若干大径となるようにピストンシール４５の中心軸を中心とするテーパ状をなして延出している。Ｒ面取り部１０４ｂは、拡径内周面部１０４ａの基部１０１とは反対側の端縁部から、軸方向に離れるほど大径となるようにピストンシール４５の中心軸に対して傾斜して延出している。Ｒ面取り部１０４ｂは、ピストンシール４５の中心軸を含む断面の形状が中間突出部１０４の内部側に中心を有する円弧状をなしている。Ｒ面取り部１０４ｂは、全体としてピストンシール４５の中心軸を中心とする円環状をなしている。 On the inner peripheral side of the intermediate projecting portion 104, an enlarged inner peripheral surface portion 104a and an R chamfered portion 104b are formed in this order from the base portion 101 side in the axial direction. The diameter-enlarged inner peripheral surface portion 104a extends from the base portion 101 in a taper shape centering on the central axis of the piston seal 45 so as to become slightly larger in the diameter in the axial direction. The R chamfered portion 104b extends from the end edge portion on the opposite side to the base portion 101 of the enlarged inner peripheral surface portion 104a so as to be inclined with respect to the central axis of the piston seal 45 so as to increase in diameter in the axial direction. ing. The R chamfered portion 104 b has an arc shape in which a cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the intermediate protruding portion 104. The R chamfered portion 104b has an annular shape centering on the central axis of the piston seal 45 as a whole.
　中間突出部１０４の外周側には、軸方向の基部１０１側から順に、縮径外周面部１０４ｃと、Ｒ面取り部１０４ｄとが形成されている。縮径外周面部１０４ｃは、基部１０１から、軸方向に離れるほど若干小径となるようにピストンシール４５の中心軸を中心とするテーパ状をなして延出している。Ｒ面取り部１０４ｄは、縮径外周面部１０４ｃの基部１０１とは反対側の端縁部から、軸方向に離れるほど小径となるようにピストンシール４５の中心軸に対し傾斜して延出している。Ｒ面取り部１０４ｄは、ピストンシール４５の中心軸を含む断面の形状が中間突出部１０４の内部側に中心を有する円弧状をなしている。Ｒ面取り部１０４ｄは、全体としてピストンシール４５の中心軸を中心とする円環状をなしている。 A reduced diameter outer peripheral surface portion 104c and an R chamfered portion 104d are formed on the outer peripheral side of the intermediate projecting portion 104 in this order from the base 101 side in the axial direction. The reduced-diameter outer peripheral surface portion 104c extends from the base portion 101 in a taper shape centering on the central axis of the piston seal 45 so as to become slightly smaller in diameter in the axial direction. The R chamfered portion 104d extends from the end edge portion of the reduced diameter outer peripheral surface portion 104c opposite to the base portion 101 in an inclined manner with respect to the central axis of the piston seal 45 so as to become smaller in diameter in the axial direction. The R chamfered portion 104 d has an arc shape in which the cross-sectional shape including the central axis of the piston seal 45 has a center on the inner side of the intermediate protruding portion 104. The R chamfered portion 104d has an annular shape centering on the central axis of the piston seal 45 as a whole.
　Ｒ面取り部１０４ｂ，１０４ｄのそれぞれの基部１０１とは反対側の端縁部が、中間突出部１０４の基部１０１とは反対側の先端面部１０４ｅに繋がっている。先端面部１０４ｅは、ピストンシール４５の軸直交面に平行をなしており、一定内径かつ一定外径でピストンシール４５の径方向に一定幅となっている。先端面部１０４ｅもピストンシール４５の中心軸を中心とする円環状をなしている。なお、中間突出部１０４の先端面部１０４ｅと内周リップ部１０２の先端面部１０２ｆとは、ピストンシール４５の軸方向の位置を合わせており、外周リップ部１０３の先端面部１０３ｇは、これらよりも基部１０１側に位置している。 The edge portions on the opposite sides of the base portions 101 of the R chamfered portions 104b and 104d are connected to the tip surface portion 104e on the opposite side of the base portion 101 of the intermediate projecting portion 104. The front end surface portion 104e is parallel to the axis orthogonal surface of the piston seal 45, and has a constant inner diameter and a constant outer diameter, and a constant width in the radial direction of the piston seal 45. The distal end surface portion 104 e also has an annular shape centering on the central axis of the piston seal 45. The tip surface portion 104e of the intermediate projecting portion 104 and the tip surface portion 102f of the inner peripheral lip portion 102 are aligned with each other in the axial direction of the piston seal 45, and the tip surface portion 103g of the outer peripheral lip portion 103 is more base than these. 101 side.
　内周リップ部１０２の縮径外周面部１０２ｄの基部１０１側と中間突出部１０４の拡径内周面部１０４ａの基部１０１側とは、湾曲面部１１４で接続されている。湾曲面部１１４は、ピストンシール４５の中心軸を含む断面の形状が、内周リップ部１０２と中間突出部１０４との間の空間に中心を有する円弧状をなしている。また、外周リップ部１０３の拡径内周面部１０３ａと中間突出部１０４の縮径外周面部１０４ｃの基部１０１側とは、湾曲面部１１５で接続されている。湾曲面部１１５は、ピストンシール４５の中心軸を含む断面の形状が、外周リップ部１０３と中間突出部１０４との間の空間に中心を有する円弧状をなしている。湾曲面部１１４，１１５のそれぞれの底位置は基部１０１を構成している。よって、基部１０１は、内周リップ部１０２および中間突出部１０４の基端部分が軸方向に厚肉であり、外周リップ部１０３の基端部分が軸方向に薄肉となっている。 The base 101 side of the reduced diameter outer peripheral surface portion 102 d of the inner peripheral lip portion 102 and the base 101 side of the enlarged inner peripheral surface portion 104 a of the intermediate protrusion 104 are connected by a curved surface portion 114. The curved surface portion 114 has an arc shape in which the cross-sectional shape including the central axis of the piston seal 45 has a center in the space between the inner peripheral lip portion 102 and the intermediate protruding portion 104. Further, the enlarged inner peripheral surface portion 103 a of the outer peripheral lip portion 103 and the base 101 side of the reduced outer peripheral surface portion 104 c of the intermediate projecting portion 104 are connected by a curved surface portion 115. The curved surface portion 115 has an arc shape in which the shape of the cross section including the central axis of the piston seal 45 has a center in the space between the outer peripheral lip portion 103 and the intermediate projecting portion 104. The bottom positions of the curved surface portions 114 and 115 constitute the base portion 101. Therefore, in the base 101, the base end portions of the inner peripheral lip portion 102 and the intermediate projecting portion 104 are thick in the axial direction, and the base end portion of the outer peripheral lip portion 103 is thin in the axial direction.
　そして、本実施形態においては、内周リップ部１０２と中間突出部１０４との間に、図４Ｂに示すように内周リップ部１０２と中間突出部１０４とを連結する連結部１２０が設けられている。図３Ａに示すように、連結部１２０は、ピストンシール４５の中心軸を中心とする円弧状をなしており、ピストンシール４５の周方向つまり基部１０１の周方向にそれぞれ等間隔で離間して複数（具体的には８カ所）形成されている。その結果、内周リップ部１０２と中間突出部１０４との間の連結部１２０が形成されていない部分がスリット１２１となっている。スリット１２１も、ピストンシール４５の中心軸を中心とする円弧状をなしており、ピストンシール４５の周方向つまり基部１０１の周方向にそれぞれ等間隔で離間して複数（具体的には８カ所）形成されている。一つのスリット１２１の周方向長さは一つの連結部１２０の周方向長さよりも長くなっている。言い換えれば、一つの連結部１２０とその周方向両端とピストンシール４５の中心とを結んで形成される扇形の中心角よりも、一つのスリット１２１とその周方向両端とピストンシール４５の中心とを結んで形成される扇形の中心角の方が大きくなっている。 In the present embodiment, a connecting portion 120 that connects the inner peripheral lip portion 102 and the intermediate protruding portion 104 is provided between the inner peripheral lip portion 102 and the intermediate protruding portion 104 as shown in FIG. 4B. Yes. As shown in FIG. 3A, the connecting portion 120 has an arc shape centered on the central axis of the piston seal 45, and a plurality of connecting portions 120 are spaced apart at equal intervals in the circumferential direction of the piston seal 45, that is, in the circumferential direction of the base portion 101. (Specifically, 8 places) are formed. As a result, a portion where the connecting portion 120 between the inner peripheral lip portion 102 and the intermediate protruding portion 104 is not formed is a slit 121. The slits 121 also have an arc shape centered on the central axis of the piston seal 45, and a plurality of slits 121 are spaced apart at equal intervals in the circumferential direction of the piston seal 45, that is, in the circumferential direction of the base 101 (specifically, eight locations). Is formed. The circumferential length of one slit 121 is longer than the circumferential length of one connecting portion 120. In other words, rather than the fan-shaped central angle formed by connecting one connecting portion 120 and both circumferential ends thereof and the center of the piston seal 45, one slit 121 and both circumferential ends thereof and the center of the piston seal 45 are connected. The central angle of the fan shape formed by tying is larger.
　連結部１２０は、基部１０１とは反対側の先端面部１２０ａが、ピストンシール４５の軸直交面に平行をなしており、一定内径かつ一定外径でピストンシール４５の径方向に一定幅となっている。連結部１２０は、円弧状の先端面部１２０ａの周方向の両側の一対の側面部１２０ｂ，１２０ｂが、基部１０１から離れるほど互いの間隔が狭くなるように、連結部１２０の中心を通るピストンシール４５の中心軸と平行な線に対し線対称をなして傾斜している。 The connecting portion 120 has a distal end surface portion 120a opposite to the base portion 101 parallel to the axial orthogonal surface of the piston seal 45, and has a constant inner diameter and a constant outer diameter and a constant width in the radial direction of the piston seal 45. Yes. The connecting portion 120 has a piston seal 45 that passes through the center of the connecting portion 120 such that the distance between the pair of side surface portions 120b, 120b on both sides in the circumferential direction of the arcuate tip surface portion 120a decreases as the distance from the base portion 101 increases. It is inclined in line symmetry with respect to a line parallel to the central axis.
　図４Ｂに示すように、連結部１２０は、内周リップ部１０２の縮径外周面部１０２ｄと中間突出部１０４の拡径内周面部１０４ａとこれらの間の湾曲面部１１４とに一体化されている。より具体的に、連結部１２０は、湾曲面部１１４に対してはピストンシール４５の軸方向および径方向の全長にわたって一体化され、縮径外周面部１０２ｄおよび拡径内周面部１０４ａに対してもピストンシール４５の軸方向のほぼ全長にわたって一体化されている。つまり、連結部１２０は、ピストンシール４５の軸方向に延びて形成されており、基部１０１からピストンシール４５の軸方向に沿って中間突出部１０４および内周リップ部１０２の突出の先端方向に延びて形成されている。連結部１２０の先端面部１２０ａは、内周リップ部１０２の最小径部１０６よりも基部１０１とは反対側まで延びており、円筒内周面部１０２ｃの軸方向中間位置まで延びている。 As shown in FIG. 4B, the connecting portion 120 is integrated with the reduced diameter outer peripheral surface portion 102d of the inner peripheral lip portion 102, the enlarged inner peripheral surface portion 104a of the intermediate projecting portion 104, and the curved surface portion 114 therebetween. . More specifically, the connecting portion 120 is integrated with the curved surface portion 114 over the entire length of the piston seal 45 in the axial direction and the radial direction, and the piston 120 is also connected to the reduced diameter outer peripheral surface portion 102d and the expanded inner peripheral surface portion 104a. The seal 45 is integrated over almost the entire length in the axial direction. That is, the connecting portion 120 is formed so as to extend in the axial direction of the piston seal 45, and extends from the base portion 101 along the axial direction of the piston seal 45 in the distal direction of the protrusion of the intermediate protruding portion 104 and the inner peripheral lip portion 102. Is formed. The front end surface portion 120a of the connecting portion 120 extends to the opposite side of the base portion 101 from the minimum diameter portion 106 of the inner peripheral lip portion 102, and extends to an intermediate position in the axial direction of the cylindrical inner peripheral surface portion 102c.
　次に、主に図２を参照して、シリンダ本体１５の周溝３２内に組み込まれてプライマリピストン１８の段部７５の円筒面部７５ａの軸方向中間位置に適正に接触し且つ周溝３２の底部１３側（図２における左側）の周壁９０から離れた基本状態（ブレーキペダルが操作される前の非制動状態）のピストンシール４５について説明する。 Next, mainly referring to FIG. 2, it is incorporated in the circumferential groove 32 of the cylinder body 15 and properly contacts the axial intermediate position of the cylindrical surface portion 75 a of the step portion 75 of the primary piston 18 and the circumferential groove 32. The piston seal 45 in the basic state (non-braking state before the brake pedal is operated) separated from the peripheral wall 90 on the bottom 13 side (left side in FIG. 2) will be described.
　この基本状態にあるとき、ピストンシール４５は、基部１０１が、シリンダ軸の直交面に平行な姿勢で最もシリンダ本体１５の開口部１６側（図２における右側）に位置している。よって、基部１０１は、周溝３２の周壁８９に対向配置され、背面部１０１ａにおいて周壁８９の平坦面部８９ａに当接している。また、最も内周側にある内周リップ部１０２が、その内周部においてプライマリピストン１８の外周面１８ａのうちの段部７５の円筒面部７５ａに接触する。このとき、内周リップ部１０２は、図４Ａ、図４Ｂに示す縮径内周面部１０２ａと拡径内周面部１０２ｂの縮径内周面部１０２ａ側の一部とが、図２に示す円筒面部７５ａに接触し、円筒面部７５ａに倣って変形前より大径の円筒面状に変形する。よって、内周リップ部１０２は、締め代をもって円筒面部７５ａに接触することになり、その際に、内径が最小の最小径部１０６が、円筒面部７５ａに対する締め代が最大となる最大締め代部位となる。そして、この最大締め代部位となる最小径部１０６まで延びて、連結部１２０が形成されている。 When in this basic state, the base 101 of the piston seal 45 is positioned closest to the opening 16 side (right side in FIG. 2) of the cylinder body 15 in a posture parallel to the plane perpendicular to the cylinder axis. Therefore, the base portion 101 is disposed to face the peripheral wall 89 of the peripheral groove 32, and abuts against the flat surface portion 89a of the peripheral wall 89 at the back surface portion 101a. Further, the inner peripheral lip portion 102 located on the innermost peripheral side contacts the cylindrical surface portion 75a of the stepped portion 75 of the outer peripheral surface 18a of the primary piston 18 at the inner peripheral portion thereof. At this time, the inner peripheral lip portion 102 has a reduced diameter inner peripheral surface portion 102a shown in FIGS. 4A and 4B and a part of the enlarged inner peripheral surface portion 102b on the reduced inner peripheral surface portion 102a side as shown in FIG. It contacts 75a and deforms into a cylindrical surface with a larger diameter than before deformation following the cylindrical surface portion 75a. Therefore, the inner peripheral lip portion 102 comes into contact with the cylindrical surface portion 75a with a tightening margin, and at this time, the minimum diameter portion 106 having the smallest inner diameter is the maximum tightening margin portion where the tightening margin with respect to the cylindrical surface portion 75a is maximized. It becomes. Then, the connecting portion 120 is formed so as to extend to the minimum diameter portion 106 serving as the maximum fastening allowance portion.
　また、基本状態にあるとき、ピストンシール４５は、円筒内周面部１０２ｃと拡径内周面部１０２ｂの円筒内周面部１０２ｃ側の一部とが、ピストン１８の円筒面部７５ａからシリンダ径方向に離れ、円筒面部７５ａとの間に隙間部１２５を形成する。この隙間部１２５は、ピストンシール４５の中心軸を中心とする円環状をなしており、シリンダ軸方向の底部１３側（図２における左側）に抜けている。そして、連結部１２０は、この隙間部１２５の基部１０１側の端部位置よりも基部１０１とは反対側まで延びている。 Further, when in the basic state, the piston seal 45 is such that the cylindrical inner peripheral surface portion 102c and a part of the enlarged inner peripheral surface portion 102b on the cylindrical inner peripheral surface portion 102c side are separated from the cylindrical surface portion 75a of the piston 18 in the cylinder radial direction. A gap portion 125 is formed between the cylindrical surface portion 75a. The gap portion 125 has an annular shape centered on the central axis of the piston seal 45, and extends to the bottom 13 side (left side in FIG. 2) in the cylinder axis direction. The connecting portion 120 extends to the opposite side of the base portion 101 from the end portion position of the gap portion 125 on the base portion 101 side.
　また、基本状態にあるとき、ピストンシール４５は、最も外周側にある外周リップ部１０３が、その最も外周側の円筒外周面部１０３ｄにおいて周溝３２の溝底部８８に当接している。また、このとき、中間突出部１０４は、自然状態と同様の状態になっており、その先端面部１０４ｅがシリンダ軸の直交面に平行をなしている。中間突出部１０４は、内周リップ部１０２と同等の長さで外周リップ部１０３よりもシリンダ本体１５の底部１３側（図２における左側）に延出している。 When the piston seal 45 is in the basic state, the outermost peripheral lip 103 of the piston seal 45 is in contact with the groove bottom 88 of the peripheral groove 32 at the outermost cylindrical outer peripheral surface 103d. At this time, the intermediate projecting portion 104 is in a state similar to the natural state, and the tip surface portion 104e is parallel to the orthogonal surface of the cylinder axis. The intermediate projecting portion 104 has a length equivalent to that of the inner peripheral lip portion 102 and extends to the bottom 13 side (left side in FIG. 2) of the cylinder body 15 from the outer peripheral lip portion 103.
　ここで、基本状態にあるとき、中間突出部１０４は、その先端面部１０４ｅの全体が周溝３２の周壁９０の平坦面部９０ａにシリンダ径方向の位置を合わせている。中間突出部１０４は、この平坦面部９０ａにシリンダ軸方向に向かい合い、この平坦面部９０ａに当接可能となるように配置されている。但し、このとき、中間突出部１０４は、平坦面部９０ａを含む周壁９０からシリンダ軸方向に離間している。 Here, when in the basic state, the intermediate projecting portion 104 has the tip end surface portion 104e entirely aligned with the flat surface portion 90a of the peripheral wall 90 of the peripheral groove 32 in the cylinder radial direction. The intermediate projecting portion 104 is arranged so as to face the flat surface portion 90a in the cylinder axial direction and be able to contact the flat surface portion 90a. However, at this time, the intermediate protrusion 104 is separated from the peripheral wall 90 including the flat surface portion 90a in the cylinder axial direction.
　また、基本状態にあるとき、内周リップ部１０２は、その先端面部１０２ｆが周溝３２の周壁９０のテーパ面部９０ｂおよびＲ面取り部９０ｃとプライマリピストン１８の段部７５のテーパ面部７５ｃとにシリンダ径方向の位置を合わせている。内周リップ部１０２は、これらテーパ面部９０ｂ、Ｒ面取り部９０ｃおよびテーパ面部７５ｃに向かい合うように配置されている。但し、このとき、内周リップ部１０２は、テーパ面部９０ｂおよびＲ面取り部９０ｃを含む周壁９０からシリンダ軸方向に離間しており、テーパ面部７５ｃからもシリンダ軸方向に離間している。また、このとき、内周リップ部１０２の先端面部１０２ｆは、周壁９０の平坦面部９０ａにシリンダ径方向の位置を重ね合わせることはない。 Further, when in the basic state, the inner peripheral lip portion 102 has a front end surface portion 102f which is connected to the tapered surface portion 90b and the R chamfered portion 90c of the peripheral wall 90 of the peripheral groove 32 and the tapered surface portion 75c of the step portion 75 of the primary piston 18 The radial position is matched. The inner peripheral lip portion 102 is disposed so as to face the tapered surface portion 90b, the R chamfered portion 90c, and the tapered surface portion 75c. However, at this time, the inner peripheral lip portion 102 is separated in the cylinder axial direction from the peripheral wall 90 including the tapered surface portion 90b and the R chamfered portion 90c, and is also separated in the cylinder axial direction from the tapered surface portion 75c. At this time, the tip end surface portion 102f of the inner peripheral lip portion 102 does not overlap the position in the cylinder radial direction on the flat surface portion 90a of the peripheral wall 90.
　さらに、基本状態にあるとき、連結部１２０の先端面部１２０ａは、周溝３２の周壁９０のテーパ面部９０ｂと周壁９０のテーパ面部９０ｂより溝底部８８側の平坦面部９０ａとの境界部１２７にシリンダ径方向位置を合わせている。先端面部１２０ａは、この境界部１２７にシリンダ軸方向に向かい合うように配置されている。言い換えれば、連結部１２０の先端面部１２０ａは、テーパ面部９０ｂと平坦面部９０ａとの両方にシリンダ径方向位置を合わせており、テーパ面部９０ｂと平坦面部９０ａとの両方にシリンダ軸方向に向かい合うように配置されている。 Further, when in the basic state, the front end surface portion 120a of the connecting portion 120 is cylinder-bound at a boundary portion 127 between the tapered surface portion 90b of the peripheral wall 90 of the peripheral groove 32 and the flat surface portion 90a on the groove bottom portion 88a side. The radial position is matched. The front end surface portion 120a is disposed so as to face the boundary portion 127 in the cylinder axial direction. In other words, the distal end surface portion 120a of the connecting portion 120 is aligned with the cylinder radial position on both the tapered surface portion 90b and the flat surface portion 90a, and faces both the tapered surface portion 90b and the flat surface portion 90a in the cylinder axial direction. Has been placed.
　図示せぬブレーキペダル側から入力がなく、図２に示すように、プライマリピストン１８がポート７６を開口溝４７に開口させる基本位置（非制動位置）にあるときに、ピストンシール４５は、内周リップ部１０２および基部１０１の内周部が、プライマリピストン１８の段部７５の円筒面部７５ａの位置にあって、基部１０１の内周部がポート７６の一部にシリンダ軸方向の位置を重ね合わせるように構成されている。 When there is no input from the brake pedal (not shown) and the primary piston 18 is in a basic position (non-braking position) for opening the port 76 into the opening groove 47 as shown in FIG. The inner peripheral portion of the lip portion 102 and the base portion 101 is at the position of the cylindrical surface portion 75 a of the step portion 75 of the primary piston 18, and the inner peripheral portion of the base portion 101 overlaps a part of the port 76 with the position in the cylinder axial direction. It is configured as follows.
　そして、ブレーキペダル側から入力があって、図５Ａに示すように、プライマリピストン１８がシリンダ本体１５の底部１３側（図５Ａ、図５Ｂにおける左側）へ移動すると、プライマリピストン１８は、段部７５のシリンダ本体１５の開口部１６側（図５Ａ、図５Ｂにおける右側）のテーパ面部７５ｂにおいて、ピストンシール４５の基部１０１のＲ面取り部１０１ｂに当接してピストンシール４５を押圧する。すると、ピストンシール４５はプライマリピストン１８と一体に移動し、その結果、図５Ａに示すように、周溝３２内で周壁９０側に移動して基部１０１が周壁８９から離れる。これとともに、中間突出部１０４の先端面部１０４ｅが周壁９０の平坦面部９０ａに当接する。 When there is an input from the brake pedal side and the primary piston 18 moves to the bottom 13 side of the cylinder body 15 (left side in FIGS. 5A and 5B) as shown in FIG. At the tapered surface 75b on the opening 16 side of the cylinder main body 15 (the right side in FIGS. 5A and 5B), the piston seal 45 is pressed against the R chamfered portion 101b of the base 101 of the piston seal 45. Then, the piston seal 45 moves integrally with the primary piston 18, and as a result, as shown in FIG. 5A, the piston seal 45 moves toward the peripheral wall 90 in the peripheral groove 32, and the base 101 is separated from the peripheral wall 89. At the same time, the front end surface portion 104 e of the intermediate projecting portion 104 abuts on the flat surface portion 90 a of the peripheral wall 90.
　プライマリピストン１８がシリンダ本体１５の底部１３側（図５Ａ、図５Ｂにおける左側）へさらに移動すると、内周リップ部１０２はプライマリピストン１８とともに移動する力を受けるが、周溝３２の周壁９０に当接する中間突出部１０４が連結部１２０で連結された内周リップ部１０２を引っ張ってその移動を抑制する。これにより、内周リップ部１０２がプライマリピストン１８の段部７５とシリンダ本体１５の摺動内径部２９との隙間に入り込んで、これらに噛み込まれてしまうことを抑制する。 When the primary piston 18 further moves to the bottom 13 side of the cylinder body 15 (left side in FIGS. 5A and 5B), the inner peripheral lip portion 102 receives a force that moves together with the primary piston 18, but it hits the peripheral wall 90 of the peripheral groove 32. The intermediate projecting portion 104 that is in contact pulls the inner peripheral lip portion 102 connected by the connecting portion 120 to suppress the movement thereof. As a result, the inner peripheral lip portion 102 is prevented from entering the gap between the stepped portion 75 of the primary piston 18 and the sliding inner diameter portion 29 of the cylinder body 15 and being caught therein.
　しかも、このとき、ピストンシール４５は、周壁９０の平坦面部９０ａに当接していて実質的に停止状態にある中間突出部１０４に対して、テーパ面部７５ｂで押圧される、基部１０１のＲ面取り部１０１ｂがシリンダ本体１５の底部１３側（図５Ａ、図５Ｂにおける左側）へ移動するが、ピストンシール４５には、基部１０１のＲ面取り部１０１ｂを中心として、中間突出部１０４の先端面部１０４ｅ側を溝底部８８側に移動させる方向のモーメントが生じる。その結果、図５Ｂに示すように、中間突出部１０４は先端面部１０４ｅが溝底部８８に近づくように若干回転する。このときも、中間突出部１０４に連結部１２０で連結された内周リップ部１０２は、テーパ面部９０ｂで周壁９０への接触が抑制されながら、中間突出部１０４に引っ張られてこれと一体に移動して、プライマリピストン１８の段部７５から径方向に離間してテーパ面部９０ｂの平坦面部９０ａ側に当接するとともに、シリンダ本体１５の摺動内径部２９よりも径方向外側に位置する。これにより、内周リップ部１０２がプライマリピストン１８の段部７５とシリンダ本体１５の摺動内径部２９との隙間に入り込むことをさらに抑制することができる。 Moreover, at this time, the piston seal 45 is in contact with the flat surface portion 90a of the peripheral wall 90 and is pressed by the tapered surface portion 75b against the intermediate protrusion portion 104 that is substantially in a stopped state. 101b moves to the bottom 13 side (the left side in FIGS. 5A and 5B) of the cylinder body 15, but the piston seal 45 has the tip surface portion 104e side of the intermediate protrusion 104 centered on the R chamfered portion 101b of the base 101. A moment in the direction of movement toward the groove bottom 88 is generated. As a result, as shown in FIG. 5B, the intermediate projecting portion 104 slightly rotates so that the front end surface portion 104 e approaches the groove bottom portion 88. Also at this time, the inner peripheral lip portion 102 connected to the intermediate projecting portion 104 by the connecting portion 120 is pulled by the intermediate projecting portion 104 and moved integrally with the tapered surface portion 90b while being prevented from contacting the peripheral wall 90. Then, it is spaced apart from the stepped portion 75 of the primary piston 18 in the radial direction and abuts against the flat surface portion 90 a side of the tapered surface portion 90 b, and is positioned radially outward from the sliding inner diameter portion 29 of the cylinder body 15. Thereby, it is possible to further suppress the inner peripheral lip portion 102 from entering the gap between the step portion 75 of the primary piston 18 and the sliding inner diameter portion 29 of the cylinder body 15.
　プライマリピストン１８がシリンダ本体１５の底部１３側（図５Ａ、図５Ｂにおける左側）へさらに移動すると、ピストンシール４５は、中間突出部１０４が周壁９０の平坦面部９０ａに当接した状態が維持され移動が規制される。このため、ピストンシール４５は、段部７５のテーパ面部７５ｂに乗り上げてポート７６を越えポート７６を閉塞して、プライマリ圧力室８５とプライマリ補給路４８との連通を遮断する。なお、この位置を含んで、この位置からプライマリピストン１８がシリンダ本体１５の底部１３側（図５Ａ、図５Ｂにおける左側）に位置する範囲では、ピストンシール４５がプライマリ圧力室８５とプライマリ補給路４８との間を遮断してプライマリ圧力室８５を密封する。この状態では、基本的に、大気圧であるプライマリ補給路４８の液圧よりもプライマリ圧力室８５の液圧の方が高くなり、プライマリ圧力室８５内のブレーキ液が図１に示すプライマリ吐出路２７から車輪側の制動用シリンダに供給される。 When the primary piston 18 further moves to the bottom 13 side (the left side in FIGS. 5A and 5B) of the cylinder body 15, the piston seal 45 moves while maintaining the state where the intermediate protrusion 104 is in contact with the flat surface portion 90 a of the peripheral wall 90. Is regulated. For this reason, the piston seal 45 rides on the tapered surface portion 75 b of the stepped portion 75, crosses the port 76, closes the port 76, and blocks communication between the primary pressure chamber 85 and the primary supply path 48. In addition, the piston seal 45 includes the primary pressure chamber 85 and the primary supply passage 48 in a range including this position and the position where the primary piston 18 is located on the bottom 13 side of the cylinder body 15 (left side in FIGS. 5A and 5B). And the primary pressure chamber 85 is sealed. In this state, basically, the hydraulic pressure in the primary pressure chamber 85 is higher than the hydraulic pressure in the primary replenishment passage 48, which is atmospheric pressure, and the brake fluid in the primary pressure chamber 85 flows into the primary discharge passage shown in FIG. 27 to the wheel-side brake cylinder.
　上記ポート７６の閉塞後、プライマリピストン１８が、さらにシリンダ本体１５の底部１３側（図５Ａ、図５Ｂにおける左側）へ移動すると、ピストンシール４５は、基部１０１がテーパ面部７５ｂを乗り越えて外径部７４に乗り上げる。これとともに内周リップ部１０２がテーパ面部７５ｂに乗り上げ、その後、内周リップ部１０２が外径部７４に乗り上げる。そして、ピストンシール４５は、上記したプライマリ圧力室８５の液圧上昇によって周溝３２内で周壁８９側に移動する。これにより、中間突出部１０４および内周リップ部１０２が周壁９０から離れるとともに基部１０１が背面部１０１ａにおいて周壁８９に当接する。 After the port 76 is closed, when the primary piston 18 further moves to the bottom 13 side of the cylinder body 15 (left side in FIGS. 5A and 5B), the piston seal 45 has an outer diameter portion with the base 101 overcoming the tapered surface portion 75b. Get on 74. At the same time, the inner peripheral lip portion 102 rides on the tapered surface portion 75 b, and then the inner peripheral lip portion 102 rides on the outer diameter portion 74. The piston seal 45 moves toward the peripheral wall 89 in the peripheral groove 32 due to the increase in the hydraulic pressure in the primary pressure chamber 85 described above. Thereby, the intermediate | middle protrusion part 104 and the internal peripheral lip | rip part 102 leave | separate from the surrounding wall 90, and the base 101 contact | abuts to the surrounding wall 89 in the back surface part 101a.
　上記のようにプライマリピストン１８がシリンダ本体１５の底部１３側（図５Ａ、図５Ｂにおける左側）へ移動した状態から、制動を解除するために図示略のブレーキペダルを戻し始めると、図１に示す間隔調整部７９によってプライマリピストン１８が図２に示す基本位置に戻ろうとする。このプライマリピストン１８の移動によってプライマリ圧力室８５の容積が拡大していく。その際に、ブレーキ配管を介してのブレーキ液の戻りがプライマリ圧力室８５の容積拡大に追いつかなくなってしまうと、大気圧であるプライマリ補給路４８の液圧とプライマリ圧力室８５の液圧とが等しくなった後、プライマリ圧力室８５内の液圧は負圧となり、大気圧であるプライマリ補給路４８の液圧よりもプライマリ圧力室８５の液圧の方が低くなる。すると、このプライマリ圧力室８５内の負圧が、ピストンシール４５の基部１０１の外周リップ部１０３側を周壁８９から離間させるように変形させるとともに外周リップ部１０３を溝底部８８から離間させるように変形させる。これにより、周溝３２とピストンシール４５との間に隙間ができ、この隙間の流路を介して、プライマリ圧力室８５にプライマリ補給路４８からブレーキ液が補給される。これにより、プライマリ圧力室８５の液圧を負圧状態から大気圧に戻すことができる。 When the primary piston 18 moves to the bottom 13 side of the cylinder body 15 (left side in FIGS. 5A and 5B) as described above and starts to return a brake pedal (not shown) to release the braking, it is shown in FIG. The primary piston 18 attempts to return to the basic position shown in FIG. The movement of the primary piston 18 increases the volume of the primary pressure chamber 85. At that time, if the return of the brake fluid through the brake pipe cannot catch up with the increase in the volume of the primary pressure chamber 85, the hydraulic pressure in the primary replenishment path 48 and the hydraulic pressure in the primary pressure chamber 85, which are atmospheric pressures, are obtained. After equalization, the hydraulic pressure in the primary pressure chamber 85 becomes negative, and the hydraulic pressure in the primary pressure chamber 85 becomes lower than the hydraulic pressure in the primary supply path 48, which is atmospheric pressure. Then, the negative pressure in the primary pressure chamber 85 is deformed so that the outer peripheral lip 103 side of the base 101 of the piston seal 45 is separated from the peripheral wall 89 and the outer peripheral lip 103 is separated from the groove bottom 88. Let As a result, a gap is formed between the circumferential groove 32 and the piston seal 45, and the brake fluid is replenished from the primary replenishment path 48 to the primary pressure chamber 85 through the flow path of this gap. Thereby, the hydraulic pressure in the primary pressure chamber 85 can be returned from the negative pressure state to the atmospheric pressure.
　ここで、ピストンシール４５に連結部１２０を設定するに当たり、図３Ａに示すスリット１２１のピストンシール４５の中心軸を中心とした形成角度θを、次式により設定するのが好ましい。 Here, in setting the connecting portion 120 to the piston seal 45, it is preferable to set the formation angle θ around the central axis of the piston seal 45 of the slit 121 shown in FIG.
　θ≦（３６０／（Ｄ＊π））＊（（３８４＊δｍａｘ＊Ｅ＊Ｉ）／５（Ｗ／（ｂ＊Ｌ）））１／４ Θ ≦ (360 / (D * π)) * ((384 * δmax * E * I) / 5 (W / (b * L))) 1/4
　上式において、δｍａｘは、内周リップ部１０２が内径方向に押し下げられる許容変位、Ｗは、テーパ面部７５ｂを摺動する際に内周リップ部１０２のスリット１２１の幅当たりにかかる径方向反力、Ｌは、スリット１２１の幅（Ｌ＝Ｄ＊π＊θ／３６０）、ｂは内周リップ部１０２の軸方向長さ、Ｈは内周リップ部１０２の径方向高さ、Ｄはプライマリピストン１８のテーパ面部７５ｂのピストンシール４５の接触位置の径、Ｉは断面二次モーメント（Ｉ＝ｂｈ３／１２）、Ｅはヤング率である。 In the above equation, δmax is an allowable displacement with which the inner peripheral lip portion 102 is pushed down in the inner diameter direction, and W is a radial reaction force applied per width of the slit 121 of the inner peripheral lip portion 102 when sliding on the tapered surface portion 75b. , L is the width of the slit 121 (L = D * π * θ / 360), b is the axial length of the inner peripheral lip 102, H is the radial height of the inner peripheral lip 102, and D is the primary piston. 18 diameter of the contact position of the piston seal 45 of the tapered surface portion 75b of, I is the second moment (I = bh 3/12) , E is the Young's modulus.
　上記した特許文献１に記載されたマスタシリンダは、ピストンに摺接するピストンシールをシリンダ本体の周溝内に配設している。このマスタシリンダでは、ピストンシールとして、円環状の基部と、基部の内周側から突出してピストンの外周面に摺接する内周リップ部と、基部の外周側から突出してシリンダ本体の周溝に当接する外周リップ部と、基部の内周リップ部と外周リップ部との間から外周リップ部よりも先まで突出する中間突出部とを有するものを用いている。また、上記した特許文献２に記載されたマスタシリンダには、環状ベース部と、その内外周から突出する内周リップ部および外周リップ部とを有するカップ型シールをピストンの環状溝内に設け、この環状溝のカップ型シールとシリンダ本体のシリンダ孔との間に、シリンダ孔に摺動する摺動リングを設けている。 In the master cylinder described in Patent Document 1 described above, a piston seal that is in sliding contact with the piston is disposed in a circumferential groove of the cylinder body. In this master cylinder, as a piston seal, an annular base, an inner peripheral lip projecting from the inner peripheral side of the base and slidingly contacting the outer peripheral surface of the piston, and projecting from the outer peripheral side of the base project against the circumferential groove of the cylinder body. What has the outer peripheral lip part which touches, and the intermediate | middle protrusion part which protrudes from the space | interval between the inner peripheral lip part and outer peripheral lip part of a base ahead of an outer peripheral lip part is used. Further, in the master cylinder described in Patent Document 2 described above, a cup-type seal having an annular base portion, an inner peripheral lip portion and an outer peripheral lip portion protruding from the inner and outer periphery thereof is provided in the annular groove of the piston, A sliding ring that slides in the cylinder hole is provided between the cup-shaped seal of the annular groove and the cylinder hole of the cylinder body.
　特許文献１に記載されたマスタシリンダでは、ピストンが移動するとピストンとともにピストンシールが移動してその内周リップ部がピストンとシリンダ本体との隙間に入り込んでしまう可能性がある。これに対して、上記実施形態のマスタシリンダ１１によれば、シリンダ本体１５の周溝３２内に設けられるピストンシール４５に、内周リップ部１０２と中間突出部１０４とを連結する連結部１２０が設けられているため、内周リップ部１０２がプライマリピストン１８とともに移動しようとしても、周溝３２の周壁９０に当接する中間突出部１０４が内周リップ部１０２を引っ張ってその移動を抑制する。したがって、内周リップ部１０２がプライマリピストン１８とシリンダ本体１５との隙間に入り込むことを抑制可能となり、プライマリピストン１８の移動によるピストンシール４５への影響を抑制可能となる。 In the master cylinder described in Patent Document 1, when the piston moves, the piston seal moves together with the piston, and the inner peripheral lip portion may enter the gap between the piston and the cylinder body. On the other hand, according to the master cylinder 11 of the above embodiment, the connecting portion 120 that connects the inner peripheral lip portion 102 and the intermediate protruding portion 104 to the piston seal 45 provided in the peripheral groove 32 of the cylinder body 15 is provided. Therefore, even if the inner peripheral lip portion 102 tries to move together with the primary piston 18, the intermediate protrusion 104 that contacts the peripheral wall 90 of the peripheral groove 32 pulls the inner peripheral lip portion 102 and suppresses the movement. Therefore, it is possible to suppress the inner peripheral lip portion 102 from entering the gap between the primary piston 18 and the cylinder body 15, and it is possible to suppress the influence on the piston seal 45 due to the movement of the primary piston 18.
　なお、特許文献２に記載されたマスタシリンダでは、ベース部に厚肉部分が形成されているが、内周リップ部および外周リップ部はシリンダ本体やピストンに摺接することはなく、よって、この厚肉部分は、ピストンの移動によるカップ型シールへの影響に対して寄与するものではない。 In the master cylinder described in Patent Document 2, a thick portion is formed in the base portion. However, the inner peripheral lip portion and the outer peripheral lip portion do not slidably contact the cylinder body or the piston. The meat portion does not contribute to the influence on the cup-type seal due to the movement of the piston.
　また、上記実施形態のマスタシリンダ１１によれば、連結部１２０が基部１０１の周方向にそれぞれ離間して複数設けられているため、内周リップ部１０２の柔軟性低下を抑制できる。 Further, according to the master cylinder 11 of the above embodiment, since a plurality of connecting portions 120 are provided apart from each other in the circumferential direction of the base portion 101, it is possible to suppress a decrease in flexibility of the inner peripheral lip portion 102.
　また、連結部１２０が、基部１０１から中間突出部１０４の先端方向に延びて形成されているため、成形が容易となる。 In addition, since the connecting portion 120 is formed to extend from the base portion 101 toward the distal end of the intermediate projecting portion 104, molding becomes easy.
　また、連結部１２０の先端が、テーパ面部９０ｂと平坦面部９０ａとの境界部１２７に向かい合うように配置されている。このため、内周リップ部１０２をテーパ面部９０ｂに対向させることができ、内周リップ部１０２と周壁９０との距離を確保できる。 Also, the tip of the connecting portion 120 is disposed so as to face the boundary portion 127 between the tapered surface portion 90b and the flat surface portion 90a. For this reason, the inner peripheral lip part 102 can be made to oppose the taper surface part 90b, and the distance of the inner peripheral lip part 102 and the peripheral wall 90 is securable.
　また、連結部１２０は、内周リップ部１０２の最大締め代部位である最小径部１０６まで延びて形成されている。このため、最小径部１０６の剛性を連結部１２０で高めることができ、内周リップ部１０２のプライマリピストン１８への面圧を高めることができる。 Further, the connecting portion 120 is formed to extend to the minimum diameter portion 106 that is the maximum fastening allowance portion of the inner peripheral lip portion 102. For this reason, the rigidity of the minimum diameter portion 106 can be increased by the connecting portion 120, and the surface pressure of the inner peripheral lip portion 102 to the primary piston 18 can be increased.
　ここで、ピストンシール４５を、図６，図７に示すように一部変更しても良い。つまり、図６に示すように、内周リップ部１０２の基部１０１からの突出長さを中間突出部１０４よりも短くしたり、連結部１２０を短くして拡径内周面部１０２ｂの最小径部１０６側の位置まで形成したりすることができる。なお、連結部１２０を短くする場合でも、少なくとも最小径部１０６の位置まで延びているのが好ましい。 Here, the piston seal 45 may be partially changed as shown in FIGS. That is, as shown in FIG. 6, the projection length of the inner peripheral lip portion 102 from the base 101 is shorter than the intermediate projection portion 104, or the connecting portion 120 is shortened to reduce the minimum diameter portion of the enlarged inner peripheral surface portion 102 b. It can be formed up to the position on the 106 side. Even when the connecting portion 120 is shortened, it is preferable that it extends at least to the position of the minimum diameter portion 106.
　また、図７に示すように、内周リップ部１０２の先端面部１０２ｆおよび中間突出部１０４の先端面部１０４ｅの位置まで連結部１２０を延ばしたり、内周リップ部１０２の略一定肉厚の先端部１０９をなくしたり、外周リップ部１０３の薄肉部１１２に径方向に貫通するスリット１３０を形成したり、内周リップ部１０２の基部１０１からの突出長さを中間突出部１０４よりも短くして中間突出部１０４の基部１０１とは反対側の端部に径方向に貫通するスリット１３１を形成したりすることも可能である。なお、内周リップ部１０２の先端面部１０２ｆおよび中間突出部１０４の先端面部１０４ｅの位置まで連結部１２０を延ばすと、先端面部１０２ｆ，１０４ｅが軸方向にオフセットしている場合、連結部１２０の先端面部１２０ａはテーパ面状をなす。 Further, as shown in FIG. 7, the connecting portion 120 is extended to the position of the front end surface portion 102f of the inner peripheral lip portion 102 and the front end surface portion 104e of the intermediate projecting portion 104, or the front end portion of the inner peripheral lip portion 102 having a substantially constant thickness. 109, or a slit 130 penetrating in the radial direction in the thin-walled portion 112 of the outer peripheral lip 103, or an intermediate length of the inner peripheral lip 102 that protrudes from the base 101 shorter than the intermediate protruding portion 104. It is also possible to form a slit 131 penetrating in the radial direction at the end of the protrusion 104 opposite to the base 101. When the connecting portion 120 is extended to the positions of the front end surface portion 102f of the inner peripheral lip portion 102 and the front end surface portion 104e of the intermediate projecting portion 104, when the front end surface portions 102f and 104e are offset in the axial direction, the front end of the connecting portion 120 The surface portion 120a has a tapered surface shape.
　なお、外周リップ部１０３の薄肉部１１２に径方向に貫通するスリット１３０を形成したり、中間突出部１０４の基部１０１とは反対側の端部にスリット１３１を形成しておくことにより、上記した制動を解除する際に、周壁８９とピストンシール４５との間により広い流路を形成することができ、プライマリ補給路４８のブレーキ液をプライマリ圧力室８５に円滑に補給することができる。 The slit 130 penetrating in the radial direction is formed in the thin portion 112 of the outer peripheral lip 103, or the slit 131 is formed at the end opposite to the base 101 of the intermediate projecting portion 104 as described above. When releasing the braking, a wider flow path can be formed between the peripheral wall 89 and the piston seal 45, and the brake fluid in the primary supply path 48 can be smoothly supplied to the primary pressure chamber 85.
　なお、以上の実施形態においては、プライマリ側のシール構造部ＳＰを例にとり詳細に説明したが、セカンダリ側のシール構造部ＳＳも同様の構造となっているため、同様の効果を奏することができ、同様の変更が可能となる。 In the above embodiment, the primary-side seal structure portion SP has been described in detail as an example, but the secondary-side seal structure portion SS has the same structure, and thus the same effect can be achieved. Similar changes are possible.
　以上の実施形態は、ブレーキ液の吐出路とリザーバに連通する補給路とを有する有底筒状のシリンダ本体と、該シリンダ本体内に移動可能に配設され、該シリンダ本体との間に前記吐出路へ液圧を供給する圧力室を形成するピストンと、前記シリンダ本体に形成された周溝内に設けられ内周が前記ピストンに摺接して前記補給路と前記圧力室との間を密封するピストンシールとを有し、該ピストンシールが、円環状の基部と、該基部の内周側から突出して前記ピストンの外周面に摺接する内周リップ部と、前記基部の外周側から突出して前記シリンダ本体の前記周溝に当接する外周リップ部と、前記基部の前記内周リップ部と前記外周リップ部との間から該外周リップ部よりも先まで突出する中間突出部と、を備えてなるマスタシリンダにおいて、前記内周リップ部と前記中間突出部との間には、前記ピストンシールの軸方向に延びて形成され、前記内周リップ部と前記中間突出部とを連結する連結部が設けられていることを特徴とする。このように、シリンダ本体の周溝内に設けられるピストンシールに、内周リップ部と中間突出部とを連結する連結部が設けられているため、内周リップ部がピストンとともに移動しようとしても、周溝の周壁に当接する中間突出部が内周リップ部を引っ張ってその移動を抑制する。したがって、ピストンの移動によるシリンダ本体とピストンとの間への内周リップ部の入り込みを抑制することが可能となる。 The above embodiment is provided with a bottomed cylindrical cylinder body having a brake fluid discharge path and a replenishment path communicating with the reservoir, and is movably disposed in the cylinder body. A piston that forms a pressure chamber that supplies hydraulic pressure to the discharge path, and an inner circumference that is provided in a circumferential groove formed in the cylinder body and that is in sliding contact with the piston to seal between the supply path and the pressure chamber A piston seal that protrudes from the outer peripheral side of the base, and an annular base, an inner peripheral lip that protrudes from the inner peripheral side of the base and slidably contacts the outer peripheral surface of the piston, An outer peripheral lip portion that comes into contact with the peripheral groove of the cylinder body, and an intermediate protruding portion that protrudes from between the inner peripheral lip portion and the outer peripheral lip portion of the base portion to beyond the outer peripheral lip portion. Master cylinder A connecting portion is provided between the inner peripheral lip portion and the intermediate projecting portion so as to extend in the axial direction of the piston seal, and connects the inner peripheral lip portion and the intermediate projecting portion. It is characterized by being. In this way, since the piston seal provided in the circumferential groove of the cylinder body is provided with a connecting portion that connects the inner peripheral lip portion and the intermediate protruding portion, even if the inner peripheral lip portion tries to move together with the piston, The intermediate protrusion that contacts the peripheral wall of the peripheral groove pulls the inner peripheral lip and suppresses the movement thereof. Therefore, it is possible to suppress the inner peripheral lip portion from entering between the cylinder body and the piston due to the movement of the piston.
　また、前記連結部が、前記基部の周方向にそれぞれ離間して複数設けられているため、内周リップ部の柔軟性低下を抑制できる。 Moreover, since a plurality of the connecting portions are provided apart from each other in the circumferential direction of the base portion, it is possible to suppress a decrease in flexibility of the inner peripheral lip portion.
　また、前記連結部が、前記基部から前記中間突出部の先端方向に延びて形成されているため、成形が容易となる。 Further, since the connecting portion is formed to extend from the base portion toward the distal end of the intermediate projecting portion, molding is facilitated.
　また、前記周溝の前記シリンダ本体の底部側の周壁における前記周溝の開口側には、テーパ面部が形成され、前記連結部の先端は、前記テーパ面部と、前記周壁の前記テーパ面部より前記周溝の底部側の壁面部との境界部に向かい合うように配置されているため、内周リップ部をテーパ面部に対向させることができ、その周壁との距離を確保できる。 Further, a tapered surface portion is formed on the opening side of the circumferential groove on the circumferential wall on the bottom side of the cylinder body of the circumferential groove, and the tip of the coupling portion is formed by the tapered surface portion and the tapered surface portion of the circumferential wall. Since it arrange | positions so that it may face the boundary part with the wall surface part by the side of the bottom part of a surrounding groove, an inner peripheral lip part can be made to oppose a taper surface part, and the distance with the surrounding wall can be ensured.
　また、前記連結部が、少なくとも前記内周リップ部の最大締め代部位まで延びて形成されているため、最大締め代部位の剛性を連結部で高めることができ、内周リップ部のピストンへの面圧を高めることができる。 Further, since the connecting portion is formed to extend to at least the maximum tightening margin portion of the inner peripheral lip portion, the rigidity of the maximum tightening margin portion can be increased by the connecting portion, and the inner peripheral lip portion to the piston can be increased. The surface pressure can be increased.
　本発明のマスタシリンダによれば、ピストンの移動によるシリンダ本体とピストンとの間への内周リップ部の入り込みを抑制することが可能となる。 According to the master cylinder of the present invention, it is possible to prevent the inner peripheral lip from entering between the cylinder body and the piston due to the movement of the piston.
　１１　　マスタシリンダ
　１２　　リザーバ
　１３　　底部
　１５　　シリンダ本体
　１６　　開口部
　１８　　プライマリピストン（ピストン）
　１８ａ　　外周面
　１９　　セカンダリピストン（ピストン）
　２６　　セカンダリ吐出路（吐出路）
　２７　　プライマリ吐出路（吐出路）
　３０，３２　　周溝
　３５，４５　　ピストンシール
　３８　　セカンダリ補給路（補給路）
　４８　　プライマリ補給路（補給路）
　６８　　セカンダリ圧力室（圧力室）
　８５　　プライマリ圧力室（圧力室）
　８８　　溝底部（周溝の底部）
　９０　　周壁（シリンダ本体の底部側の周壁）
　９０ａ　　平坦面部（壁面部）
　９０ｂ　　テーパ面部
　１０１　　基部
　１０２　　内周リップ部
　１０３　　外周リップ部
　１０４　　中間突出部
　１０６　　最小径部（最大締め代部位）
　１２０　　連結部
　１２７　　境界部 11 Master cylinder 12 Reservoir 13 Bottom 15 Cylinder body 16 Opening 18 Primary piston (piston)
18a Outer peripheral surface 19 Secondary piston (piston)
26 Secondary discharge path (discharge path)
27 Primary discharge path (discharge path)
30, 32 Circumferential groove 35, 45 Piston seal 38 Secondary supply path (supply path)
48 Primary supply path (supply path)
68 Secondary pressure chamber (pressure chamber)
85 Primary pressure chamber (pressure chamber)
88 groove bottom (bottom of circumferential groove)
90 Perimeter wall (peripheral wall on the bottom side of the cylinder body)
90a Flat surface (wall surface)
90b Tapered surface portion 101 Base portion 102 Inner peripheral lip portion 103 Outer peripheral lip portion 104 Intermediate projecting portion 106 Minimum diameter portion (maximum fastening allowance portion)
120 connecting part 127 boundary part

Claims (5)

  1. 　ブレーキ液の吐出路とリザーバに連通する補給路とを有する有底筒状のシリンダ本体と、
    　該シリンダ本体内に移動可能に配設され、該シリンダ本体との間に前記吐出路へ液圧を供給する圧力室を形成するピストンと、
    　前記シリンダ本体に形成された周溝内に設けられ内周が前記ピストンに摺接して前記補給路と前記圧力室との間を密封するピストンシールとを有し、
    　該ピストンシールが、
    　円環状の基部と、
    　該基部の内周側から突出して前記ピストンの外周面に摺接する内周リップ部と、
    　前記基部の外周側から突出して前記シリンダ本体の前記周溝に当接する外周リップ部と、
    　前記基部の前記内周リップ部と前記外周リップ部との間から該外周リップ部よりも先まで突出する中間突出部と、を備え、
    　前記内周リップ部と前記中間突出部との間には、前記ピストンシールの軸方向に延びて形成され、前記内周リップ部と前記中間突出部とを連結する連結部が設けられているマスタシリンダ。     A bottomed cylindrical cylinder body having a brake fluid discharge path and a supply path communicating with the reservoir;
    A piston that is movably disposed within the cylinder body, and that forms a pressure chamber between which the fluid pressure is supplied to the discharge passage;
    A piston seal provided in a circumferential groove formed in the cylinder body and having an inner circumference slidingly contact the piston and sealing between the supply path and the pressure chamber;
    The piston seal is
    An annular base,
    An inner peripheral lip projecting from the inner peripheral side of the base and slidingly contacting the outer peripheral surface of the piston;
    An outer peripheral lip that protrudes from the outer peripheral side of the base and contacts the peripheral groove of the cylinder body;
    An intermediate projecting portion projecting from between the inner peripheral lip portion and the outer peripheral lip portion of the base to the end of the outer peripheral lip portion;
    A master provided between the inner peripheral lip portion and the intermediate projecting portion is formed to extend in the axial direction of the piston seal and connects the inner peripheral lip portion and the intermediate projecting portion. Cylinder.
  2. 　前記連結部は、前記基部の周方向にそれぞれ離間して複数設けられている請求項１記載のマスタシリンダ。 2. The master cylinder according to claim 1, wherein a plurality of the connecting portions are provided separately from each other in the circumferential direction of the base portion.
  3. 　前記連結部は、前記基部から前記中間突出部の先端方向に延びて形成されている請求項１または２記載のマスタシリンダ。 The master cylinder according to claim 1 or 2, wherein the connecting portion is formed to extend from the base portion toward a distal end of the intermediate projecting portion.
  4. 　前記周溝の前記シリンダ本体の底部側の周壁における前記周溝の開口側には、テーパ面部が形成され、
    　前記連結部の先端は、前記テーパ面部と、前記周壁の前記テーパ面部より前記周溝の底部側の壁面部との境界部に向かい合うように配置されている請求項１乃至３のいずれか一項に記載のマスタシリンダ。     A tapered surface portion is formed on the opening side of the circumferential groove on the circumferential wall on the bottom side of the cylinder body of the circumferential groove,
    4. The front end of the connecting portion is disposed so as to face a boundary portion between the tapered surface portion and a wall surface portion on the bottom side of the circumferential groove from the tapered surface portion of the circumferential wall. 5. The master cylinder described in 2.
  5. 　前記連結部は、少なくとも前記内周リップ部の最大締め代部位まで延びて形成されている請求項１乃至４のいずれか一項に記載のマスタシリンダ。 The master cylinder according to any one of claims 1 to 4, wherein the connecting portion is formed to extend to at least a maximum fastening allowance portion of the inner peripheral lip portion.
PCT/JP2013/058948 2012-10-31 2013-03-27 Master cylinder WO2014069015A1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US14/430,317 US10053076B2 (en) 2012-10-31 2013-03-27 Master cylinder
IN2357DEN2015 IN2015DN02357A (en) 2012-10-31 2013-03-27
JP2014544334A JP5903496B2 (en) 2012-10-31 2013-03-27 Master cylinder
CN201380048515.2A CN104661885B (en) 2012-10-31 2013-03-27 Master cylinder
DE112013005217.2T DE112013005217T5 (en) 2012-10-31 2013-03-27 master cylinder
RU2015110698/11A RU2595334C1 (en) 2012-10-31 2013-03-27 Main cylinder
KR1020157007927A KR102089119B1 (en) 2012-10-31 2013-03-27 Master cylinder

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JP (1) JP5903496B2 (en)
KR (1) KR102089119B1 (en)
DE (1) DE112013005217T5 (en)
IN (1) IN2015DN02357A (en)
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DE102016215962A1 (en) * 2016-08-25 2018-03-01 Robert Bosch Gmbh Braking device for a vehicle
JP6785313B2 (en) * 2016-10-04 2020-11-18 日立オートモティブシステムズ株式会社 Master cylinder
DE102016223758A1 (en) 2016-11-30 2018-05-30 Robert Bosch Gmbh Master brake cylinder, brake system
EP3543568B1 (en) * 2018-03-19 2021-01-06 Carl Freudenberg KG Sealing ring, sealing arrangement and use of a sealing arrangement

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JP2008111495A (en) * 2006-10-31 2008-05-15 Bosch Corp Cup seal and master cylinder using the same
JP2008290708A (en) * 2007-05-22 2008-12-04 Robert Bosch Gmbh Master cylinder comprising a seal and an associated groove promoting resupply
DE102009052568A1 (en) * 2009-11-10 2011-05-12 Lucas Automotive Gmbh Sealing arrangement for sealing pressure piston arranged movably in housing of brake cylinder for hydraulic motor vehicle brake system, has sealing element attached in housing of brake cylinder

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RU2254248C2 (en) * 2003-04-14 2005-06-20 Открытое акционерное общество "Автоагрегат" Hydraulic master cylinder
JP4417233B2 (en) * 2004-09-30 2010-02-17 日立オートモティブシステムズ株式会社 Master cylinder
WO2008050633A1 (en) 2006-10-23 2008-05-02 Bosch Corporation Cup seal and master cylinder using the same
JP6060265B2 (en) * 2013-08-30 2017-01-11 日立オートモティブシステムズ株式会社 Master cylinder

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JP2008105444A (en) * 2006-10-23 2008-05-08 Bosch Corp Master cylinder
JP2008111495A (en) * 2006-10-31 2008-05-15 Bosch Corp Cup seal and master cylinder using the same
JP2008290708A (en) * 2007-05-22 2008-12-04 Robert Bosch Gmbh Master cylinder comprising a seal and an associated groove promoting resupply
DE102009052568A1 (en) * 2009-11-10 2011-05-12 Lucas Automotive Gmbh Sealing arrangement for sealing pressure piston arranged movably in housing of brake cylinder for hydraulic motor vehicle brake system, has sealing element attached in housing of brake cylinder

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JPWO2014069015A1 (en) 2016-09-08
IN2015DN02357A (en) 2015-09-04
DE112013005217T5 (en) 2015-08-06
US20150246664A1 (en) 2015-09-03
KR20150079574A (en) 2015-07-08
US10053076B2 (en) 2018-08-21
RU2595334C1 (en) 2016-08-27
CN104661885A (en) 2015-05-27
KR102089119B1 (en) 2020-03-13
JP5903496B2 (en) 2016-04-13

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